KroneckerDelta is 0 or 1, thus any positive power returns itself.
Simplify Interval.as_relational().
Handle KroneckerDelta in summations and products.

Fixes issues 3481 and 3482.
Use solve only once on the system of equations.

Use solve only once on the system of equations, instead of calling
it for each equation.
Issue #3581:Implement arg.rewrite(atan2)
mark some solve tests as slow
factor_terms can remove radical from +/- base
Specify minimal version of the coverage module for bin/coverage_report.py
Fix exception while series expansion of function with multiple args:

    >>> zeta(x, y).series(y, 0, 2)
    Traceback (most recent call last):
      File "<console>", line 1, in <module>
      File "/home/sk/sympy/py3k-sympy/sympy/core/expr.py", line 2360, in
    series
        s1 = self._eval_nseries(x, n=n, logx=None)
      File "/home/sk/sympy/py3k-sympy/sympy/core/function.py", line 502, in
    _eval_nseries
        if (self.func.nargs == 1 and args0[0]) or self.func.nargs > 1:
    TypeError: unorderable types: tuple() > int()
Add missing tests in test_loggamma(), see issue 2317
Add Ben Fishbein to the .mailmap file
Merge pull request #1979 from smichr/slow

mark some solve tests as slow
Merge branch 'master' of github.com:sympy/sympy
Fix issue #3738
Add test cases for issue #3738
Add other two test cases
Merge pull request #1928 from amitjamadagni/trig

Issue #3581:Implement arg.rewrite(atan2)
simplify -1 and I handling in Mul.flatten

The best of 3 runs of the core test suite gave, in seconds,

master: 43, 48, 57
now: 36, 36, 45

So this appears to be a little faster and leads to a more compact result.
watch for unevaluated I**e
modify equals and is_constant

** Inline notes describe why the minimal_polynomial is not being used
at present to prove an nsimplify result. solve, however, may be able
to prove that an expression is zero by getting a self-consistent solution
when solving for a surd of the expression. An test was added for this.

** In addition, cancel is used on the expression to try facilitate
simplification to zero (and an expression that motivated the change
has been included).

** don't use equals in sign and abs because it can be very slow

Thanks to Mario Pernici for finding good examples of when the
method used in equals is going to take a long time to solve.
The discussion that I had with him is on the PR 1925 page.