Also remove some unused parameters/functions

If compiling according to a C++ version before C++11, then define
std::to_string ourselves.

Add a to_wstring version as well

As std::to_string() for floating point types uses %.6f as floating
point format converter, instead of %G, it needs special care.

To preserve ftos() behavior (which is expected to use the %G format
converter), it no longer uses to_string().

This fallback to std::map & std::set for older compilers

Use UNORDERED_SET as an example in decoration and ore biome sets

Use UNORDERED_MAP as an example in nameidmapping

 - Fix unused c_sand member warning in Valleys Mapgen
 - Fix some code style
 - Make some std::string params const ref

Add documentation, move files to a proper place and avoid memory leaks.
Make it work with most kind of texts, and allow backgrounds too.

Colored chat working as expected for both freetype and non-freetype builds. @nerzhul improvements * Add unit tests * Fix coding style * move guiChatConsole.hpp to client/

Gives a convenient way to check a player's password.

This entirely bypasses the SRP protocol, so should be used
with great care.

This function is not intended to be used
in-game, but solely by external protocols, where no
authentication of the minetest engine is provided, and
also only for protocols, in which the user already gives the
server the plaintext password.

Examples for good use are the classical http form, or irc,
an example for a bad use is a password change dialog inside
formspec.

Users should be aware that they lose the advantages of the SRP
protocol if they enter their passwords for servers outside the
normal entry box, like in in-game formspec menus,
or through irc /msg s,

This patch also fixes an auth.h mistake which has mixed up the
order of params inside the decode_srp_verifier_and_salt function.

Zeno-: Added errorstream message for invalid format when I committed

Also, change the escape character to the more standard \x1b
Thus, it can be used in the future for translation or colored text,
for example.

Backports 10 commits, with 8 commits
actually affecting source code:

https://github.com/est31/csrp-gmp/compare/695822e45d9ca48b75b4ec1af1b4eea19139f8b1...deaa11a7c29a730087380da231e785909ad21630

Changes:
  * Fix indentation.
  * Pass strings by const reference.
  * Merge Strfnd and WStrfnd into one class instead of copying them.
  * Remove trailing spaces.
  * Fix variable names.
  * Move to util.
  * Other miscellaneous style fixes.

* No function overloading
* Adhere coding style and with method names following
  lowercase_underscore_style
* Use std::string in external API, handling these is
  much more fun

* Sky: rename Box => m_box and inline getBoundingBox
* Uniformize aabbox3d<f32> to aabb3f

There it isn't needed.

This adds a chat console the server owner can use for administration
or to talk with players.
It runs in its own thread, which makes the user interface immune to
the server's lag, behaving just like a client, except timeout.
As it uses the same console code as the f10 console, things like nick
completion or a scroll buffer basically come for free.
The terminal itself is written in a general way so that adding a
client version later on is just about implementing an interface.

Fatal errors are printed after the console exists and the ncurses
terminal buffer gets cleaned up with endwin(), so that the error still
remains visible.

The server owner can chose their username their entered text will
have in chat and where players can send PMs to.
Once the username is secured with a password to prevent anybody to
take over the server, the owner can execute admin tasks over the
console.

This change includes a contribution by @kahrl who has improved ncurses
library detection.

These names are reserved for the compiler/library implementations.

-> Remove memory allocation bugs
-> Merge changes from upstream, enabling customizeable memory allocation

  * Rename everything.
    * Strip J prefix.
    * Change UpperCamelCase functions to lowerCamelCase.
  * Remove global (!) semaphore count mutex on OSX.
  * Remove semaphore count getter (unused, unsafe, depended on internal
    API functions on Windows, and used a hack on OSX).
  * Add `Atomic<type>`.
  * Make `Thread` handle thread names.
  * Add support for C++11 multi-threading.
  * Combine pthread and win32 sources.
  * Remove `ThreadStarted` (unused, unneeded).
  * Move some includes from the headers to the sources.
  * Move all of `Event` into its header (allows inlining with no new includes).
  * Make `Event` use `Semaphore` (except on Windows).
  * Move some porting functions into `Thread`.
  * Integrate logging with `Thread`.
  * Add threading test.

This bypass had to be re-enabled as some users reported issues,
even after the iconv build fix.

While utf8_to_wide works well, wide_to_utf8 is quite broken
on android, for some reason, and some devices (unrelated from build
configuration).

This was caused by the use the non-threadsafe SharedBuffer in a
threaded context.