use list, iterator on the stack instead of heap
big rewrite.

way too many global variables (elements in the
t_biddler struct), so i moved some stuff to be locals
and some stuff to be local static.

still some issues:
  now some changes (quantization, reset postion) dont take
  effect until the measure has fully completed.
fixed sync issues with reset_position and quant_n
added error global to disable in case of unexpected errors

hopefully reduces the chances of crashing max/msp
renamed x->filter to x->first_sym
sanity checks on quantization and slice parameters