Cell use output() field with 3 values: ACTIVE/INACTIVE/PREDICT

and remove corresponding set/get-predictState/activeState

TODO check they correspond usage<->name
TODO what is learnState?
Cell make output a time vector

cell.output(time) so it remembers history
Cell make also learnState a time vector

cell.getLearnState(time)
implemented by CircularList buffer
rename to DendriteSegment
TemporalPooler rename fn to less confusing name - neighborhoodCells

used to be getNeighbors (same as in cell.getNeighbors)
TemporalPooler remove init()