This commit introduces Raycast, a Lua user object, which can be
used to perform a raycast on the map. The ray is continuable, so one can
also get hidden nodes (for example to see trough glass).
Instead of create fake events on the stack on each loop call (Game::run), verify is queue is empty or not and handle event directly if there is.
This prevents fake ClientEvent creation & memory allocations
Same fix is also applied on ClientEnvironment, & rename getClientEvent to getClientEnvEvent to match ClientEnvEvent object
* squashed: CSM: Implement register_globalstep
* Re-use fatal error mechanism from server to disconnect client on CSM error
* Little client functions cleanups
* squashed: CSM: add core.after function
* core.after is shared code between client & server
* ModApiUtil get_us_time feature enabled for client
- Increase ContentFeatures serialization version
- Color property and palettes for nodes
- paramtype2 = "color", "colored facedir" or "colored wallmounted"
* Environment code refactoring
* Cleanup includes & class declarations in client & server environment to improve build speed
* ServerEnvironment::m_gamedef is now a pointer to Server instead of IGameDef, permitting to cleanup many casts.
* Cleanup IGameDef
* Move ITextureSource* IGameDef::getTextureSource() to Client only.
* Also move ITextureSource *IGameDef::tsrc() helper
* drop getShaderSource, getSceneManager, getSoundManager & getCamera abstract call
* drop unused emerge() call
* cleanup server unused functions (mentionned before)
* Drop one unused parameter from ContentFeatures::updateTextures
* move checkLocalPrivilege to Client
* Remove some unnecessary casts
* create_formspec_menu: remove IWritableTextureSource pointer, as client already knows it
* Fix some comments
* Change required IGameDef to Server/Client pointers
* Previous change that game.cpp sometimes calls functions with Client + InventoryManager + IGameDef in same functions but it's the same objects
* Remove duplicate Client pointer in GUIFormSpecMenu::GUIFormSpecMenu
* drop ClientMap::sectorWasDrawn which is unused
