PLEASE NOTE: the current release is very instable on Windows Max8

mubu.track:
- added getmedian method

mubu.knn:
- added getmedian method

- new examples & tutorials

mubu.play:
- fixed speed change

mubu:
- added options startchannel / numchannels to read audio messages
- fixed open editor by double click
- several minor bug fixes

imubu::
- wave & multiwave editors can add samples on empty track with mouse
- added inactive buffer color
- several minor bug fixes