Suggested changes to the old assumptions

These are the changes that I think should be made to the old assumptions. 

Because these changes are likely to be contentious, I have split each change into a separate commit. I have also only made the change to assumptions.py. I don't want to waste time propagating the change throughout the code-base until we agree that the change should be made. 

If you think it would be even better to make each change a separate pull request, let me know. I don't know if that will make things easier or harder when propagating the changes throughout the code-base, however. 
On Wed, Oct 01, 2014 at 08:49:07AM -0700, Aaron Meurer wrote:
>    In sympy/core/assumptions.py:
> 
>  >      'noninteger     ==  real & !integer',
>  > -    '!zero        ==  nonzero',
>  > +    'nonzero        ==  complex & !zero',
> 
>    What uses to you envision for nonzero? I had in mind something like "1/x
>    is a finite number if x is nonzero".

That's fine.  And oo fits in this paradigm.