Uses system provided libgmp if found, if not it falls back to mini-gmp.

This fixes the problem where 0.4.12-dev versions were erroneously shown as
0.4.11-dev because the tag was added on a separate branch.  It also fixes a
similar issue when builders didn't fetch new tags when updating.

This also removes the number-of-commits-since-tag field, since it's
incompatible with this.  Said field doesn't seem to be useful anyway if you
have the commit hash.

Split unit tests into separate files under src/unittest/
Give better unittest diagnostics
Clean up some code

Don't reinvent freetype detection, use working one from cmake.

Move debug streams to log.cpp|h

Move GUI-related globals to clientlauncher

Move g_settings and g_settings_path to settings.cpp|h

Move g_menuclouds to clouds.cpp|h

Move g_profiler to profiler.cpp|h

  * Combine client and server man pages.
  * Update unit test options and available databases in man page.
  * Add `--worldname` to man page.
  * Fix a bunch of places where `"Minetest"` was used directly instead of `PROJECT_NAME`.
  * Disable server build by default on all operating systems.
  * Make `ENABLE_FREETYPE` not fail if FreeType isn't found.
  * Enable LevelDB, Redis, and FreeType detection by default.
  * Remove the `VERSION_PATCH_ORIG` hack.
  * Add option to search for and use system JSONCPP.
  * Remove broken LuaJIT version detection.
  * Rename `DISABLE_LUAJIT` to `ENABLE_LUAJIT`.
  * Rename `minetest_*` variables in `version.{h,cpp}` to `g_*`.
  * Clean up style of CMake files.

* Remove --enable-unittests and --disable-unittests and add --do-unittests function
* --do-unittests function will exit 0 on success.
* minetest and minetestserver binaries are launched with --do-unittests in travis build.

NetworkPacket.cpp:
* Remove some deprecated functions, we must use streaming interface
* m_data converted from u8* to std::vector<u8>
* Add an exporter to forge packet to Connection object
* implement operator << std::wstring. n
* implement operator << std::string
* dynamic resize when write packet content.
* fix string writing and performances.
* create ServerCommandFactory, used by client to get useful informations about packet processing (sending).
  * Reliability
  * Transmit channel
* Implement putRawString for some ugly char (_INIT packet), and use it.
* Many packet read and write migrated
* Implement oldForgePacket to interface writing with current connection
* fix U8/char/bool writing
* fix string writing and performances.
* add some missing functions
* Use v3s16 read instead of reading x,y,z separately
* Add irr::video::SColor support into packets
* Add some missing handlers
* Add a template function to increase offset
* Throw a serialization error on packet reading (must be improved)

PacketFactories:
* Create ServerCommandFactory, used by client to get useful informations about packet processing (sending).
* Create ClientCommandFactory, used by server to get useful informations about packet processing (sending).

Client.cpp:
* implement NetworkPacket ::Send interface.
* Move packet handlers to a dedicated file
* Remove Client::Send(SharedBuffer)

Server.cpp:
* implement NetworkPacket ::Send interface.
* Rewrite all packets using NetworkPacket
* Move packet handlers to a dedicated file
* Remove Server::Send(SharedBuffer)

ClientIface.cpp:
* Remove sendToAll(SharedBuffer<u8>)

Connection.hpp rework:
* Remove duplicate include
* Remove duplicate negation
* Remove a useless variable
* Improve code performance by using a m_peers_list instead of scanning m_peers map
* Remove Connection::Send(SharedBuffer)
* Fix useafterfree into NetworkPacket Sending
* Remove unused Connection::sendToAll

Test.cpp:
* Remove dead code
* Update tests to use NetworkPackets

Misc:
* add new wrappers to Send packets in client, using NetworkPacket
* Add NetworkPacket methods for Connection
* coding style fix
* dead code since changes cleanup
* Use v3s16 read instead of reading x,y,z separately in some packets
* Use different files to handle packets received by client and server
* Cleanup: Remove useless includes

ok @Zeno-
Tested by @Zeno- @VanessaE and @nerzhul on running servers

main.cpp rework * Move ClientLauncher class to a dedicated file * ClientLauncher now owns print_video_modes and speed_tests functions (they are only called by him) * Move GameParams to shared/gameparams.h because it's shared between server and client and launcher need to know it * Move InputHandlers class to client/inputhandler.h * Cleanup includes

* Move networkcode to a dedicated directory
* Rename clientserver.h to network/networkprotocol.h (Better name) and sanitize some includes
* Create object NetworkPacket
  * It stores command (opcode) and data separated
  * It also stores peer_id
  * Data reading can be done by using a streaming interface
* Change packet routing analysis
  * Remove old conditional analysis
  * Now uses function pointed analysis and add connection state ({Client,Server}::handlers)
  * Connection state permit to categorize condition to handle before analyze packets
  * Create a handler for depreciated messages, instead of duplicating code

Remove software exception translator function, simplifying exception handler
macros.  FatalSystemExceptions are left unhandled.

Add -Wall to Debug modes for all compilers and -Wabi for non-MSVC
Use /Ox for MSVC Release mode (potentially higher optimization than /O2)

This reverts commit 839c4a99.

-O1 results in executables that are completely useless for actuall debugging

f7d65091 introduces error when no endian.h found in the system.

Since "CHECK_INCLUDE_FILE" returns empty string instead of "0", when
"cmake_config.h" is generated it has "#define CMAKE_HAVE_ENDIAN_H " line.
Later we have "#define HAVE_ENDIAN_H CMAKE_HAVE_ENDIAN_H" in the
"config.h", an thus "HAVE_ENDIAN_H" is also empty sting. Because of
this, "#if HAVE_ENDIAN_H" is incorrect preprocessor directive.

Signed-off-by: Craig Robbins <kde.psych@gmail.com>

serialize.h: use machine native byte swapping if available, fall-back to previous generic method if not (supported for GCC using endian.h, detection done in cmake) write/readARGB8() - just write 32-bit color in one op, instead of 4 1-byte ops cleanup: removed unneeded buffer init for some serialize-out functions use a #define for the fixed point factor in read/writeF1000()

nodemetadata.cpp, nodetimer.cpp
	optimzation: simpler deserialize node position method

staticobject.cpp:
	cleanup: use util/serialize.h inlines instead of its own de/serialization

serialize.cpp:
	minor optimization/cleanup: avoid generation of unneeded string temporary

CMakeLists.txt, cmake_config.h.in: detection of endian.h

config.h: added HAVE_ENDIAN_H

Commits due to feedback squashed

Signed-off-by: Craig Robbins <kde.psych@gmail.com>

- Don't create and cache an extruded mesh for every (non-node) item.
  Instead use a single one per image resolution.

- For cubic nodes reuse a single wield mesh too

- Improve lighting of the wielded item

- Increase far value of wield mesh scene camera, fixes #1770

- Also includes some minor refactorings of Camera and GenericCAO.

This also cleans up settings a bit