[sdiy] more avrsyn features

[Daniel Kruszyna]

I have a new version of my avrsyn code available at http://krue.net/avrsyn/

New Features:
  - arpeggiator!
  - delay line effect (with its own lfo)
  - configurable size note stack
  
Code Improvements:
  - allow multiple lfos
  - use hardware multiplier for MUL32X16
  - optimize phase delta table lookup
  - lfo level/modwheel bugfix
  - dca gate mode bugfix

and most likely other changes I've forgotten..

Enjoy.

-- Daniel