Cudnn r2

DownsampleFactorMax support strides: issue #2196

[CRASH] Fix scan unpickle (crash) as we added a new attribute. Also make a scan ...

Fix scan unpickle (crash) as we added a new attribute. Also make a scan opt support old pickled Subtensor.

 - Split the C code apart in between the Conv ops (the previous
   solution is not workable with the new interface).

 - Move the C code out into separate files using COp.

 - Make cudnn_helper.h provide wrappers exposing the R2 api with the
   R1 functions when possible to reduce #ifdef maze in actual function
   code.

[CRASH] Cudnn repair r1 softmax

[CRASH] Repair crash with cudnn r-1 following the removing of struct_id

Revert "Get rid of typeConstructor in Scan."

This reverts commit 7d70c3a4.

Output StorageMap content in raise_with_op

Use numpy's function to check array is contiguous

[ENH] Matrix exponential op and gradient (round 2!)