added DistKLDivCriterion CUDA implementation and a unit test for it.  Also added modified the MSE unit test to include sizeAverage tests as well (to get all code paths).
removed redundant kernels from DistKLDivCriterion and modified test.
Merge pull request #23 from jonathantompson/kl_divergence

added DistKLDivCriterion CUDA implementation and a unit test for it.