Fixed, Texture Browser Form: well, I broke "Tab" key functionality again (in previous commit)...
Maintenance: changed curly braces style to match DB2 one (hopefully not breaking anything in the process...).
Maintenance: changed private method names casing to match DB2 one.
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 ("-").