Use the new grad interface.

I don't know if argsort should have a grad defined, so I mark it as not implemented.
Make GpuCrossentropySoftmaxArgmax1HotWithBias and GpuCrossentropySoftmax1HotWithBiasDx work for bigger inputs.
Add extra debug info in verify_grad.
Fix error on the GPU for ExtractDiag.

When the output was of size 0, we where returning a numpy ndarray
instead of a CudaNdarray.

No news, as this is a fix to something new since the last release.
Make ArcsinTester pass in float32.

The old range was causing nan in float32.
pep8
Added print information when we run theano tests in batch.

This print the time used for each batch.
Add manual instruction for OpenBLAS on Ubuntu by Jianri Li
pep8
fix flymake warnings.
Merge pull request #1442 from nouiz/mixed2

[WIP] Use the new grad interface.