[ENH] Scan PushOutSeqScan

Props compile

Props tensor

props to theano/misc/pycuda_example.py

Pydotprint, fix printing of reused output and updated shared var

cuda bugfix with array over 2g

added the shared variable zero fn.

Integrate the latest version of CNMEM

This version comes with two fixes.

1/ Fix a warning due to the visibility attribute needed by Theano.
We changed const char* CNMEM_API to const char CNMEM_API* in the
declaration of cnmemGetErrorString to have the attribute between
char and star. It fixes the warning.

2/ Fix a compilation issue with CUDA 5.0 due to the missing
cudaStreamGetFlags function. It is #defined out when the Runtime
is less than 5.5 (5050 version).

Flake8 misc

changing sort.grad to work with other ndim

Mixed stuff