Changes in PGP Shell v0.6

- Fixed bugs preventing Decrypt and ASCII options from working.
- The screen is now properly cleared when calling PGP.TTP.
- You are now prompted to press a key or mouse button when PGP.TTP is done.
- Fixed a few other minor bugs in the file name processing.
- You now need to double click filename fields to bring up a file selector.
- Added more key commands for scrolling text in the View ASCII window:
      arrows and shift arrows for scrolling
      CLR/HOME for top
      SHIFT CLR/HOME for bottom.
- Fixed bug resulting left over text when a smaller ASCII file is opened while a larger one
  is already open.