Make IncSubtensor use the new NumPy API.
Make GpuSubtensor and GpuIncSubtensor use the new NumPy C API.

This simplify the *IncSubtensor code at the same time.
remove import not used.
Re-enable the caching of c code from [Gpu][Inc]Subtensor.
For Theano to always use the new NumPy C API (and so remove the warning about that).
Add blas timming.
more error info in tests.
remove commented code following code review.