Use workprec context manager to temporary change mpmath binary precision
Calling powerset() method should not produce deprecation warnings

Use is_subset(S.Reals) instead of is_real.
MinMaxBase will raise error if args are not Expr's

This also fix deprecation warnings like this:
>>> s = FiniteSet(FiniteSet(1, 2, 3))
>>> s
{{1, 2, 3}}
>>> len(s)
1
>>> s.powerset()
/usr/lib/python3.3/site-packages/sympy-0.7.5_git-py3.3.egg/sympy/functions/elementary/miscellaneous.py:334:
SymPyDeprecationWarning:

is_real has been deprecated since SymPy 0.7.6. Use is_subset(Reals)
instead. See https://github.com/sympy/sympy/issues/6212 for more info.
Merge pull request #3 from skirpichev/is_real_deprecated

MinMaxBase will raise error if args are not Expr's
Merge pull request #8268 from skirpichev/use-workprec

Use workprec context manager to temporary change mpmath binary precision
Changed deprecation for lambdify matrices

This commit changes how lambdify behaves, mostly having to do with the
deprecation plan to change the default from Matrix -> numpy.matrix to
Matrix -> numpy.array.

- No longer have the `default_array` kwarg. Everything is solved by
  passing in a custom dict for the `modules` kwarg.

- Throw warning only if expr is a matrix, and the translation for
  `Matrix` hasn't been set at all by the user. If it has, no warning
  is thrown, as the translation is intentional.
Merge pull request #8269 from amitsaha/is_real_deprecated

Calling powerset() method should not produce deprecation warnings
Merge pull request #8034 from jcrist/issue_8030

Change behavior of lambdify deprecation
Don't use _eval_sides to evaluate Equality, use is_zero instead

fixes #6116
Move _eval_sides to the Relational._eval_simplify helper
Slightly expand Equality docstring: add notes about simplification