Allow number of channels configuration in client/server mode

[vicwomg]

There are situations where one might not want to run in single channel mode (originally this change was made to save bandwidth)

Clients might want to connect to non-Jamtrip servers that are not single-channel (-n 1). This should be supported in the manual configuration, and the patching should work as expected.

[vicwomg]

in the meantime 0.1.3 has reverted to the more common 2-channel mode. Best to keep things more with the defaults, and the bandwidth impact seemed negligible in real-world testing