Changes to ZFlash v1.20:

- 'Colours' on a monochrome monitor should be restored to original values
- Error when in 'BBS mode' fixed
- Error when downloading to or uploading from a different drive or
  partition fixed
- Better error-trapping

Known bugs/features:

- When you press Ctrl-C very quickly at the beginning of a receive, the 
  machine will lock up completely.
- Because the command line can't be longer than 120 chars, the number of
  files to send is slightly limited.

Change to ZFlash v1.21:

Command line wasn't cleared properly when repeating send sequence, fixed.