Refactor processing of inequalities with oo

fixes #7775
fixes #7798
fixes #7841

this patch replaces #7800 and #7799
On Sat, Sep 13, 2014 at 02:23:57PM -0700, Aaron Meurer wrote:
>    In sympy/physics/quantum/represent.py:
> 
>  > @@ -367,7 +367,7 @@ def integrate_result(orig_expr, result, **options):
>  >      x*DiracDelta(x - x_1)*DiracDelta(x_1 - x_2)
>  >      >>> integrate_result(X_op*x_ket, x*DiracDelta(x-x_1)*DiracDelta(x_1-x_2),
>  >      ...     unities=[1])
>  > -    x*DiracDelta(x - x_2)
>  > +    -x*DiracDelta(x - x_2)*Heaviside(-x - oo) + x*DiracDelta(x - x_2)
> 
>    These seem wrong to me. Heaviside(-x - oo) can only be nonzero if -x - oo
>    is positive.

This is not "wrong".  Just a messy result.  We can't simplify this,
as -x is not known to be bounded (and oo - oo is nan).

A little summary: in this pr I did no changes in quantum module (except for fixing old
tests).