- General code cleanup
 - Unified object creation and loading
 - Specifying objects in APIs is now orthogonal (i.e. anything can take an ID,
   name string, or the raw table definition (and automatically registers if present

Add core.clear_registered_schematics() and refactor schematics somewhat

  * 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.

This reverts commit 467fc0dd.

Add schematic decoration force placement flag

Add find_surface_nodes_in_area LUA call which permit to only get the nodes which touch air. This permit to massively improve performance for mods like plantlife

Rebased by Zeno- (conflict in lua_api.txt)

Client now informs about incompatible servers from the list, this permits to prevent the protocol movements.
Server announces its supported protocol versions to master server

Also add a Lua API and chatcommand for this

Lua-api.txt: Document that paramtype='light' results in light propagation with attenuation and is essential for a light source to spread it's light

Just Markdown, no variant of it. File name intentionally
not changed to “lua_api.md” because of fear to break references
to that file. The file can still be renamed later.

Also rewrite mapgen registration for static initialization

Add minetest.get_mapgen_params()
Deprecate minetest.register_on_mapgen_init()

Also set default height_min/height_max to -31000 and 31000,
respectively, for ore and biomes