Copy GpuSubtensor to the new back-end, enable its test.
Add the opt to move IncSubtensor to the new GPU back-end.
GpuIncSubtensor continued, not finished.
A first working implementation of GpuIncSubtensor.perform()

As GpuArray don't implement += and +, we pass by another interface.
remove fct not used anymore.
Advance GpuIncSubtensor c code
Finish GpuIncSubtensor c code.
Don't include Python/NumPy include, convert the string.

Otherwise, in some platform the include fail. This is more robust.
remove the import of pycuda in the new back-end.
Fix pickling of GpuIncSubtensor
Updated OpFromGraph docstring.
Raise error if the user try to use shared variable.
Fix error msg.
Remove OpFromGraph grad_depth parameter.
pep8
cache OpFromGrad sub grad computation. This remove duplicate op creation.
OpFromGraph now compile in make_thunk().
Make OpFromGraph support shared variable.
pep8
Updated class doc of OpFromGraph