Try not to break after the variable in a default initializer.

It (arguably) looks ugly to do something like this:

    foo(a, b, c, d=
        None, e=37)

instead of this:

    foo(a, b, c,
        d=None, e=37)
Allow spaces around arithmetic operators.
Merge pull request #116 from gwelymernans/master

Try not to break after the variable in a default initializer.