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.
Client doesn't like to receive multiples SendInventory for one action, this can trigger glitches on clients (sometimes due to incorrect UDP packet ordering due to UDP protocol)
This fix issue #2544
