show error message if MIDI interface is in use instead of crashing
running status bugfix

Some MIDI interfaces send a "running status" (omitting the first message
byte, if it is the same for consecutive MIDI messages, even if the
application doesn't send it. The current menu doesn't support this, so
as a workaround it alternates bewteen note-on/off messages, because
after the first note-off message it is not tested if it is a note-on for
the rest of the transfer.
fixing some compiler warnings
allow exe files
new V1.1 release
added transfer statistics again, commented
new version V1.1