Updated, Visual mode, "Raise Floor/Ceiling/Thing to adjacent Sector/Thing" / "Lower Floor/Ceiling/Thing to adjacent Sector/Thing" actions: sectors across targeted sectors are now taken into account when determining target height.
Updated, Visual mode, "Raise Floor/Ceiling/Thing to adjacent Sector/Thing" / "Lower Floor/Ceiling/Thing to adjacent Sector/Thing" actions: the actions can now stack things on top of other things when their bounding boxes intersect.
Internal: cosmetic changes to shader update logic.
Internal: thing bounding box is now used when adding a thing to VisualBlockMap.
Error Checker mode: added "Check missing flats" check.
Error Checker mode: fixed several descriptions.
Sprite patches for sprites defined in TEXTURES are now loaded from Sprites namespace.
Some of my older texture alignment code didn't work properly when strict texture/flat handling ("mixtextureflats" game configuration flag set to false) was enabled.
Fixed some incorrect checks for missing texture ("-").
