Remove config from c key.

In particular remove nvcc.* stuff. We don't want the c_key of the config to change depending if theano.sandbox.cuda is imported or not.
Fix test in float32 and in FAST_COMPILE.
Added doc about hard_sigmoid and ultra_fast_sigmoid
Remove config from the key.
Merge pull request #1423 from nouiz/fixes

Fixes
Add on the web page the doc for images2neibs and neibs2images.
pep8
better doc.
Merge pull request #1424 from nouiz/doc

Doc neighbour
pep8
Raise understandable error on mac with anaconda.
Add python 3.3.0 in the daily buildbot.
Added Anaconda on mac installation instruction.
Merge pull request #1425 from nouiz/mac_anaconda

buildbot python 3.3.0 and Mac anaconda instruction.