MAINT: Remove unnecessary check from before swapaxes (API change)

This check was a speed optimization in the numpy code. Due to
a small change in the MapIter API, the check is now wrong in
corner cases and becomes fully unnecessary.
The previous API had not been public in any release numpy
version.
Make GPU Ops accept TensorType output gradients (transfer them to GPU)
Import as_cuda_ndarray_variable in theano.sandbox.cuda
Skip test if GPU not available
Merge pull request #1382 from lamblin/fix_gpu_grad

Make GPU Ops accept TensorType output gradients (transfer them to GPU)
Merge pull request #1378 from seberg/patch-1

MAINT: Remove unnecessary check from before swapaxes (API change)
Prevent moving "gpu_from_host" outside of scan

Detect if the inner replacement would have a different type,
so that a new gpu_from_host is not inserted in the inner graph
in replacement of the one that was just pushed out.
Same change in sequence optimization