Added linger-wt-mat to function 'clone'.
Changed names of the two popns.
In update-propn-wts-from-analogy-activns, changed wt-mat to propn-from-analogy-wt-mat
Added add-from-feeder-node!
Moved clip-to-extrema to nets.clj
Changed update-propn-net-from-utterances to update linger-wt-mat