[WIP] Mechanism for running a test multiple times with different random seeds

Allow dnn convolution to work inplace

Update aa.py, theano.sandbox.wraplinker seems not exist.

Fix few tests for the nightly buildbot

Dnn pool support of pad

adding documentation to  addbroadcast() unbroadcast() and patternbroadca...

Work around cudnn bug.

Problems to fix:
- dnn pool grad with ignore_border=False do not seam to compute the good value. Did we have a bug? Do they support it? Maybe not as it isn't documented.
- We do not tests mode=average correctly as we do not have a reference implementation.
- We do not tests pad. Need a reference implementation.

Fixes and cleanup for maxpool with padding

Check negative strides in gpu_contiguous

Escape backslashes in windows path string