default ugen onInputChanged calls onMulAddInputChanged
some ugens can simply use base onInputChanged if they only call onMulAddInputChanged
Merge remote-tracking branch 'danstowell/onMulAddInputChanged'

* danstowell/onMulAddInputChanged:
  some ugens can simply use base onInputChanged if they only call onMulAddInputChanged
  default ugen onInputChanged calls onMulAddInputChanged