A quantizer attracts the results of the preceeding modul onto a quantization 
grid q. The optional strength s  {0...1} (default 1) specifies to which 
extent the grid takes effect (1 is total quantization, 0 is no quantization 
at all). The optional offset o (default 0) shifts the whole grid by the given 
amount. Each of the 3 parameters may be constant or time variant (bpf).