B-Em with Music 2000 Midi Interface and Music 4000 Keyboard Emulation

This is a pre-release of a version of B-Em that emulates a Music 2000 MIDI interface to allow MIDI to be sent from AMPLE to any of three MIDI output ports as per Issue #36. This is based on the branch of B-Em that has the Music 4000 keyboard emulation which translates received events into key-presses on the emulated Music 4000.

This fixes a bug found in the previous pre-release where the names of the MIDI devices as saved to the config file were often corrupt.

If you fancy testing this, things to check out are:

1. What happens if you have more than one MIDI output port? Does it correctly assign up to three Music 2000 ports to those?
2. Does the Music 4000 emulation still work for you.
3. Is tape loading still good? (the MIDI I/F uses 3x6850 ACIA and tape is the other major use of these).

You can also build for Linux - instructions are on the Wiki.