Added SpatialUpSamplingNearest module.

This is a very simple SpatialUpSamplingNearest module.  It's pretty self explanatory :-)  It was from work by both myself and Arjun Jain (I shouldn't take all the credit).

I know there is a similar module in the nnx library, however this is slightly faster AND there will be a second pull request in cunn by Arjun Jain with his CUDA version of this function (he will put that up today).