Added error messages in cuda_ndarray, and a (commented) way of printing freed memory when debugging memory allocations (in the same file).

fixed optimization bugs triggered by propagation of shape 1 to unbroadcastable dims - hint: prefer broadcast_like() to alloc()

Updated Windows install instructions to say GPU does not work, also replaced refs to Python 2.7 by Python 2.6 because Python(x,y) is currently using 2.6

Fixed check of the existence of the cuda_ndarray module under Windows, where the extension is not .so

Fixed a bug reported by cityhall consisting in not calling tensor.as_tensor on arguments before calling make_node

implement/test the proposal that created shared variable must return the same type as what they received as input.

Add test for inplace operation on shared variable when the shared constructor input is casted to the same value as the internal type.