Fixes regression in async beat scheduler.
Renames it flock.scheduler.async.tempo and introduces a component-style
creator API so that it can eventually support time signatures, etc.
Merge branch 'master' into node-evaluation-refactoring

* master:
  Fixes regression in async beat scheduler. Renames it flock.scheduler.async.tempo and introduces a component-style creator API so that it can eventually support time signatures, etc.
Completely refactors nodeList/ugenNodeList behaviour.
This fixes a number of bugs and performance issues related to setting
and getting unit generator values.
Also improves performance of flock.generate() and fixes bugs in
flock.isIterable().