p: If jackd(1) is running, start mplayer with -ao jack

d96e394e-0db6-11e3-b723-001f3b596ec9
Merge branch 'p.use-jack'

If the audio is in mono, jack plays only through the left channel.
Don't know if it's fixable. In cases like that I'll just kill it.

* p.use-jack:
  p: If jackd(1) is running, start mplayer with -ao jack

293de28a-1276-11e3-8eb4-001f3b596ec9