Posted version 0.99d, minor fix for pure DOS compatibility

This is a minor fix build for pure DOS compatibility. Animated textures were defined using a foo+n naming scheme in the filenames but pure DOS doesn't accept that. It works under Win9x (where i was testing the code) so i didn't notice it. The naming scheme changed to foo_n instead, which is DOS compatible.

If you are playing Post Apocalyptic Petra under Win9x (while the GUI is running) or DOSBox this shouldn't affect you. If you are playing under a real DOS machine without Win9x running, then you need this fix for animated textures to work.

This does affect the editor, though only in a minor way (the editor wont have animated textures). I will upload a new editor build later.UP

UPDATE: I also uploaded the editor. I modified it a bit to include a list of entities that can be useful when looking at the existing maps and trying to figure out what is what. The new Petra099dEditor.zip file includes the two modified source code files but you can ignore those if you do not plan on building the editor.