midi functions

[John Donoghue]

All,

I started what could turn into a new package for midi functions based on 
the function info provided for matlab.

It is using rtmidi as the library for the midi access, still needs some 
work and doesnt have all the functions yet.


I posted to the code onto teh patch tracker [1]

If it looks ok for a start, can someone create a hg repo on octave-forge 
for it?

[1] https://savannah.gnu.org/patch/index.php?9868


JD