Fixed test_linalg.py:test_spectral_radius_bound

Was broken by a6e1769d.
This fix also includes some coding style fixes.

Remove deprecated stuff

Make scan opt before blas opt.

Fix neibs

Spectral radius bound review

Depricated scan

They should not have been used anymore as they should have been removed already.

Was accepted only in theano.function in the mode argument. Not as a theano flags.

When tring to make the grad raise an Exception with an error that the old version returned wrong answer.

Ensure sorted indices reviewed

Fix default axis for tensor.roll

In the case of a default axis argument and a 1-d tensor, don't create
flatten and reshape nodes that need to be optimized out when it's simple
enough not to do so.

NumPy docstring standard compliant. Nearly identical to the numpy.roll
docstring.

Elegantly solved with a recursive call.

added roll function and test

small fix to gpusum. It can happen that we start 2 reduction at the same time

added roll import to tests

fixed pep8 issues

Better pushout optimization