refactored TensorSharedVariable test of shared options to be able to reused them for CudaNdarrayShared.

to check for input aliasing and removed the transitivity assumption on the
aliasing.

mutable or borrowed

Make PatternSub hangdling of allow_multiple_client with dictionnary that don't define it to default to the value of the parent nod instead of False.

Also fixed tensordot to accept numpy syntax for axes.

inplace computation

and inplace operations are used we are not getting the right results. Note
that is not easy to trigger this behaviour.

re-enable neibs2images while adding it missing parameter. Warn when that we don't implement the extra parameter if they are not at their default value for now.

In that case the future behavior is not actually different from the historic
one, reducing over the last axis is exactly the same as reducing over all the
axes.

Finishes closing of #539.

Closes #539.

Closes #538 .

a < b < c was failing silently by generating the graph "lt(b,c)".  We now forbid
"boolean" comparison of the return value of __lt__, __le__, __gt__, __ge__.
We cannot forbid "boolean" comparison of TensorVariables in general, since the
syntax "if a:" is often used instead of "if a is not None:"