optimise: pause a playingsound's synths when not playing (rather than just mute)

[danstowell]

Currently the playback synths run all the time but are muted when not playing back. This is wasteful. Instead use the Pause.kr(gate, nodeID) ugen to pause/unpause synths.

Probably need each PlayingSound to have a 'supervisor synth' which listens to the clock, and manages the pausing/unpausing and the triggering too. This low-complexity synth will run continuously and pause/unpause the bigger beasts.

For each PlayingSound:

• create a group (inside playingSynthsGroup) which will hold the playersynth and the synthsynth
• create a supervisor synth added before that group

Move the trigger-from-clock logic from playersynth to supervisorsynth.

(also remove the muting currently performed in the playback synth, so can verify behaviour)

[danstowell]

Blogged how to do it here http://www.mcld.co.uk/blog/blog.php?308 now to actually implement it

[danstowell]

Closed in 7e9578fb115400d27578