Fixed, Map Analysis mode: fixed a crash when trying to dissolve an invalid sector when one of it's linedefs referenced it on the both sides.
Fixed, Sectors mode: fixed incorrect undo description when deleting sectors.
Internal: joined declaration and assignment of some more variables.
Map Analysis mode: selection color is now used when rendering affected things.
Fixed, Map Analysis mode, "Check unused things" check: checker returned false-positive results when used in Doom map format.
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.
Map Analysis, internal: some ErrorCheckers and ErrorResult had inconsistent namespaces.
Thing Edit forms, internal: optimized missing flags check a bit.