caffe conv kernel for theano. tests work, but needs integration and some...

The caffe convolution works and passes test, however, code needs some cleaning, which are marked with TODO in comments.  I created a new file, theano/sandbox/cuda/tests/test_conv_gemm.py that calls GpuConvMM. 
This is not ok.  You need to add the full license (either inline as a comment, or in a separate file that is referred to here).