removing 255 content file limitation
player state cleanup
Merge branch 'refnum' into savedgame

Conflicts:
	apps/openmw/mwworld/cellstore.cpp
	apps/openmw/mwworld/manualref.hpp
	components/esm/cellref.hpp
moved CellRef loading code to the CellRef class
added savedgame-specifc record structs for objects state
some fixes to record structs
loading/saving of some player state (cell/coordinates and some other bits)
added missing birthsign field to player state record
handle missing player specific state during load/save
reset reference to player NPC record during cleanup
on load check player record for dangling ID references
adding missing cleanup for SoundManager
improved cleanup; failed loads will now drop back into the main menu instead of crashing
store cell state in saved game files (no references yet)
removed a redundant field from object state
write references in cells to saved game file
ignore deleted references that did not came from a content file
Merge branch 'savedgame' of https://github.com/zinnschlag/openmw into savedgame
Include some required Ogre headers explicitely