#496 allow Pd to *not* automatically connect to jack

[IOhannes m zmölnig]

when using jack, Pd currently tries to automatically connect itself to the soundcard.
this is great, as it makes it easy to get audio in/out with minimal setup.

unfortunately there are some situations where this is suboptimal (when Pd's I/O is sent to another application, and one doesn't want to have both Pd's "dry" signal and the audio output of the other application on the speakers).

the attached patch adds a new flag "-noaudioconnect" to Pd's startup flags, which will prevent the automatic connection to the default soundcard)

[IOhannes m zmölnig]

apply with "git am ..."