Note:
For an example of an application of SPKitMux, see SPKitSchroeder.
SPKitSum overrides the setOutput() function for counting the number of objects using it as their input. The class also overrides getSample().
Calls SPKitProcessor::setInput().
On the first call, getSample() requests a sample from its input and stores the summed result in outputSample. On successive calls (depending on the number of the object's outputs) getSample() returns the sample in outputSample. When all outputs have received a copy of the first input sample, the object requests a new sample from its input.
getSample() returns 0 on end of input, 1 otherwise.
Kai Lassfolk / University of Helsinki / kpl@elisir.helsinki.fi