This commit adds MIDI parser subclasses for the Simon 1 GMF format and for the
SMF variant used by the Windows versions of Simon 1 and 2.
The GMF format was handled by the SMF parser, which can now be removed from
that class. It also fixes the tempos not matching the DOS interpreter.
The Simon Windows SMF variant was handled in the AGOS midi class. Moving it to
a separate parser allows for some cleaner code in that class. It now also
corrects the tempos to match those of the DOS interpreter.
This allows the SMF parser to work with MidiDriver implementations that support
multiple MIDI sources. You can set the source number when constructing the
parser. This is then passed along when MIDI messages are sent to the driver.
