[MRG] implement padding for max pool grad grad

Adding the documentation for assert_no_cpu_op #2881.

Don't assert for array sizes, just raise an exception.

[MRG] Implement c_code for GpuReshape

[MRG] softmax function that builds expression instead of using softmax op

Python23

Add theano.tensor.nnet.relu function

Fix symbol visibility in cuda_ndarray on Windows

This bundled copy will go away at a later time.