TDX Convertor

Imports: TDX, BMP, JPG, TIF, TGA, PNG
Exports: TDX, BMP, JPG, TIF, PNG

CommitLog:

Finished the first pass of the TDX Convert dialog.  It is now possible to import TDX, BMP, JPG, TIF, TGA and PNG and export as TDX, BMP, JPG, TIF or PNG (TGA export coming soon)

Closes #58