Add a tutorial on convolutions

Implementation of 2D dilated convolution/correlation.

fixed error message in op.py

Rtd theme correct

useless dimshuffle in reshape is removed

cuDNN v5 Batch Normalization

Updated Numpy copyright dates

Add some documentation on how to write gpu ops.

Change documentation theme to readthedocs and add source links

Make sure that the 'source' link in the API documentation is linked to
the specific version of the code selected with the version switcher.

if broadcastable is the same then no need to op

Update the versions tested on travis

Single stream flag

Port FFTs to gpuarray backend

Verify grad speedup

Ccw 4483 indent fix