Add GpuArray_IS_C_CONTIGUOUS and GpuArray_IS_F_CONTIGUOUS and fix GpuArr...

...ay_ISFORTRAN.

The last one should be true only if fortran and not c order:

http://docs.scipy.org/doc/numpy/reference/c-api.array.html#PyArray_ISFORTRAN
Don't 'return a', 'return 0' instead