WINTERMUTE: Remove useless Rect extra argument from fadeToColor.

It is not used anywhere, and Mnemonic has confirmed that the original
engine does NOT support anything but full screen fades.
WINTERMUTE: Introduce dirtyRectContainer
WINTERMUTE: Hook engine to dirtyRectContainer
WINTERMUTE: Multiple rects
WINTERMUTE: Hooks for optimized dirty rects
WINTERMUTE: Minimal search for duplicates and contained
WINTERMUTE: Search for close relatives
WINTERMUTE: Bail out of multirect dance if encounter huuuge rect or there's a lot of them
WINTERMUTE: Factor out huge-test.
WINTERMUTE: Remove _tempDisableDirtyRects as it duplicatres functionality in DirtyRectManager
WINTERMUTE: Fix boundaries and computations in DirtyRectContainer
WINTERMUTE: Remove bits that actually *add* pixels and try to cut away duplicate areas
WINTERMUTE: Slice up cross-shaped intersections
WINTERMUTE: Avoid adding useless rects
WINTERMUTE: Pizza-slice rects for intersections + move some bits around
WINTERMUTE: Fix isHuge
WINTERMUTE: Trim rect list as we go
WINTERMUTE: Fix fades... via hack?
WINTERMUTE: Remove oldColorMod
WINTERMUTE: Fix fallback for fades