WINTERMUTE: Detach BaseSaveThumbHelper from inheritance tree.
WINTERMUTE: Rename base_save_thumb_helper.cpp to match class-hierarchy.
WINTERMUTE: Use only const BaseGame-ref in SaveThumbHelper.
WINTERMUTE: Increase const-usage.
WINTERMUTE: Constify _width and _height in BaseRenderer.
WINTERMUTE: Protect more members in BaseRenderer.
WINTERMUTE: Improve const-usage in VideoTheoraPlayer.
WINTERMUTE: Add more const to AdResponseBox