0.8.8b1 - Directory system change, blank tile fix

Level directories and Area directories now do not contain the names of
the Levels/Areas ("Project/levels/" is the directory containing the level
"FinalFantasy"; "Project/levels/FinalFantasy" is the directory
containing the area "Midgar");

The specific directory names and file names are stored in static
constant strings that can be changed.

TileSelection transformations no longer apply to tile id 0 (the blank
tile).