MAHOUT-1464

The numNonZeroElementsPerColumn additions did not account for negative values, only counted the positive non-zero values. Fixed this in the in core and distributed case.

I added to Functions.java to create a Functions.notEqual. It may be possible to do this with the other functions but it wasn't obvious so I wrote one. The test is in MatrixOpsSuite, where is it used.

The distributed case was much simpler.

Changed tests to include negative values.
Nice. I didn't look deep enough to see that f is the column vector. I'll change that.

While we are at it, I now know about A'A (which is the slim calc?) that doesn't really compute A'. If you do similar for two different matrices:``` B.t %*% A``` does B.t ever get checkpointed?