Merge pull request #2033 from f0k/corrmm-faster-fullconv

Faster algorithms and gradients for GpuCorrMM
Make opt local_useless_subtensor convert to subsample when we reverse.
Rework the Op contract documentation and add a bit about __props__.
Disable opt in some case discovered in new tests crash with the new opt.
Fix imports for the documentation.
Fix documentation warnings in sparse/basic.py
Remove section titles in the docstring (they don't show up and cause warnings).
Fix most of the remaining warning for the doc.
Add mentions of __props__
Reflow paragraphs
Remove flops() since it's not really important.
Remove warnings about nonlocal images.
Changes following review.
Add mention of __str__ to the __props__ blurb in the tutorial.
Merge pull request #2069 from abergeron/doc

Doc
Make optimization more deterministic
Merge pull request #2060 from ziyuang/master

Resolved issue #2055
Better auto function name if we call var.eval().
small doc update on Theano vision.
skip some tests when scipy isn't available.
Add comment
Remove old deprecated stuff.