Environment & IGameDef code refactoring (#4985)

* 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

src/server.cpp

@@ -50,7 +50,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "content_abm.h"
 #include "content_sao.h"
 #include "mods.h"
-#include "sound.h" // dummySoundManager
 #include "event_manager.h"
 #include "serverlist.h"
 #include "util/string.h"
@@ -3310,29 +3309,12 @@ ICraftDefManager *Server::getCraftDefManager()
 {
 	return m_craftdef;
 }
-ITextureSource *Server::getTextureSource()
-{
-	return NULL;
-}
-IShaderSource *Server::getShaderSource()
-{
-	return NULL;
-}
-scene::ISceneManager *Server::getSceneManager()
-{
-	return NULL;
-}
 
 u16 Server::allocateUnknownNodeId(const std::string &name)
 {
 	return m_nodedef->allocateDummy(name);
 }
 
-ISoundManager *Server::getSoundManager()
-{
-	return &dummySoundManager;
-}
-
 MtEventManager *Server::getEventManager()
 {
 	return m_event;