Fixes for python 3 compatibility.
#1281: Convert to unicode early under Python 3.x. Thanks @delallea for the suggestion.
Fixed a bug introduced in previous commit.  NB: install before testing under py3k.
Fix a test in python3
Fix error not raised in python 3.

This change the behavior a little. Now int are casted into
numpy.int64. This is needed as in Python3 long have replaced int and
there are no more long! So the int case will be used in Python 3.

Forcing the type isn't a problem as we support only this type for
shape everywhere in Theano.
Add __init__.py file to have more tests installed with Theano.

This allow theano.tests() to run more tests!
fix a test when scipy is not available
Fix test in Python 3.
Enable optimization on numpy interger, not just python int.

This is needed as a previous commit changed some python int to numpy integer.

This will also make the optimization happen more frequently then before.
Fix another filter() use in scan for python3
Make test work with python3