EMI: Implement screenshot thumbnails for savegames
GRAPHICS: Initialize/Destroy _storedDisplay
EMI: Free materials as soon as they are no longer in use by any costumes.
Merge pull request #954 from chkr-private/savegame-screenshots

EMI: Implement screenshot thumbnails for savegames
Merge pull request #967 from Akz-/emi-fix-savecrash

EMI: Free materials as soon as they are no longer in use by any costumes
EMI: Fix compiler warnings for specialty texture ID.
Merge pull request #970 from JoseJX/FixUnsignedIntegerComparison

EMI: Fix compiler warnings for specialty texture ID.
EMI/GRIM: Remove unsused roll parameter from setupCamera calls.
GRIM/EMI: Rename setupCamera to better describe what it does.
EMI: Rework attaching and detaching.
EMI: Keep camera rotation matrix and add setter/getter for camera Euler Angles.
EMI: Fix displayed rotation.