In the shape feature, return to the old priority when we update the shape

Fix the enabling of gpu optimization.

Smallfix

add missing parenthesis that cause syntax error.

Made error message more explicit

Typos

Including some line-too-long fixes.

Finish the fix to the change to ShapeFeature.

Other change triggered this hidded crash.

More fix to elemwise change needed!

Fix assert import

A few typo fixes in doc

Important fix
Everything looks good

We should always use the convention name for input to function that we override!

There is more fix that are missing.

We call the shape_feature.on_attach with an empty env to help prevent change to the shape feature request change to the scan infer_shape.

I made a registration system that allow all Theano Type to tell if they allow OutputGuard to generate c code for them. This fix the dependency on sandbox code in theano/compile/mode.py file. This make it a better fix then what was done for SparseType.

Added test.