Support tilesets filetypes

[xan2622]

Tileset Builder should support every kind of tilesets used in Westwood games (RA1, TD, D2K, TS, RA2, YR).

• [ ] *.tem
• [ ] *.sno
• [ ] *.int
• [ ] *.des
• [ ] *.jun
• [ ] *.tmp
• [ ] *.R8 ...