Update comment after code review.

Fix test and update NEWS.txt

We explicitly use and -inf in the graph, so DebugMode shouldn't complain about this.

The problem was caused by the name conflict between the scan submodule and the scan function.

This reverts commit 7fa448b8.

make filter for CudaNdarray check for stride == 0 for dim == 1.

Conflicts:
	theano/compile/function.py
	theano/compile/pfunc.py
	theano/gof/fg.py
	theano/gof/type.py

Fix gpu strides crash

This commit starts a series of changes to eliminate relative and redundant imports.

- do not import theano.tests unless theano.test() function is called.
- reuse  TheanoConfigParser instance from configdefaults.