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.
UnXFAIL an XPASSing pretty_sum test
Use binding = prettyForm.MUL in several classes' printers

This makes the classes be parenthesized when used in a Pow.  This is an
alternate fix to #1788.  I changed Integral, Sum, Product, and Derivative. In
general, any kind of operator should use this, since it is printed like the
operator *times* the operand.

Also remove the special casing in print_Pow from #1788, since it was incorrect
in light of the existence of the binding settings.

This is a better fix of issue 3260.
Fix the baseline for Piecewise printing

This fixes part of issue 3354.
Add new prettyForm binding, OPEN, which parenthesizes in Add

This is useful for things like Piecewise which need to be parenthesized even
in Add.

There is code in _print_Add that handles negatives that should probably be in
prettyForm.
Pretty print Piecewise always using parentheses

This changes the binding to OPEN, which causes it to parenthesize whenever it
is in an Add, Mul, or Pow.  This results in much easier to read expressions,
especially when a Piecewise is in an Add to the left of other terms.

This finishes the fixes of issue 3354.
Fix Issue 3727 (ufuncify + erf)
Exception handled for ordering relation in plotting
Uniformity in checking whether a number is a complex number
Added test for handling Max
Increases matplotplot min version to 1.1.0
changed returns so that it is short circuited
Added unit test for lambdify

Removed the plotting test for Max(x, 5) replacing it with a unit
test for lambdify
minimum matplotlib version required = 1.1.0 in runtests.py

Added a reminder comment at plot.py to change the minimum matplotlib
version at runtests.py.
Staging the infra of a basic PDE Solver
Minor Change
Test a bug in Piecewise._eval_subs