Add some new methods to PK3StructuredReader and DirectoryReader, which get the filename with the correct case, and get a file at a particular path.
Replace backslashes in modeldef model paths with forward slashes, instead of doing the opposite, which was preventing some models from loading.
I don't know whether or not this is a good solution or not, since I don't know the UDB codebase very well.
Changed: LOKCDEFS keys are now sorted alphabetically.
Fixed, MAPINFO parser: blocks inside map definition block were parsed incorrectly when using new MAPINFO format.
Fixed, rendering: custom MODELDEF scale was applied incorrectly when "Stretched view in visual modes" option was enabled.
Updated ZDoom_DECORATE.cfg.
Updated GZDoom_MODELDEF.cfg.
Fixed, Sound Environment mode: in some cases the view was not updated after updating sound environments.
Added, Sound Environment mode: Sound environment things of currently highlighted sound environment are now highlighted.
