Conflicts:
	theano/gradient.py

Using a Feature to catch BadGradOp

Better doc of extra_ops.

added error checking and doc to reshape

documented the images2neibs ops

Change replace_all_validate to replace_all_validate_remove

Minor stuff

fix to annoying error message of sandbox/scan

Max argmax bug

Fix corner case in cvm updates, add test.

Fix wrong results that could end up with wrong shape.

The bug appeared when some shared variable was updated with itself, the
values of update expressions would be assigned to incorrect shared
variables.

Rewrite squeeze and delete SqueezeOp.