DSP: update to new audioservers API
Mandelhub: remove unnecessary not= false tests
Libs/mandelhub: add some missing functionality; refactor
editor: actually kill scheduled items
Pattern: refactoring + adding tempo and quantization

- defpat now works on the basis of a global metronome
  - defpat patterns can be quantized
- do-play-pattern refactored
  - tried to make the structure clearer, but still too big
Example Instruments: make percussion instruments freq-aware.
Patterns: make default freq & amp setable through defpat