UnXFAIL Wester test_I1 with nsimplify
UnXFAIL Wester test_I2 with nsimplify
UnXFAIL Wester test_K2 with nsimplify
UnXFAIL Wester test_M2
Implement __contains__ for SingleFiniteDistribution.

Fixes issue 3964: Test failure in master: __contains__ deprecated in test_finite_rv.py
https://code.google.com/p/sympy/issues/detail?id=3964
Properly reset warning filters in tests.

Fixes issue 2492: Better way to test warnings
https://code.google.com/p/sympy/issues/detail?id=2492
Increment stacklevel when wrapping warnings.warn().
Print enhanced asserts' lhs and rhs each on its own line.
Add missing __future__ import print_function.
Get rid of nsimplify: test_C14, test_C15
Revert "UnXFAIL Wester test_I1 with nsimplify"

This reverts commit 3f29ef613e354bdeea87bd18a5e6f1bfe70d79b4.
Revert "UnXFAIL Wester test_I2 with nsimplify"

This reverts commit 61f065ad9ca06f567777a054bf7bce64d6dd2938.
Revert "UnXFAIL Wester test_K2 with nsimplify"

This reverts commit c648253cb69df6f4f3e1e6fe76159b98ea253600.
Merge branch 'master' into wester-nsimplify
Get rid of nsimplify: fix test_C17 with radsimp
Get rid of nsimplify: fix test_C18
Get rid of nsimplify: convert nsimplify -> simplify and mark tests as XFAILed
Merge branch 'master' into tests2
XFAIL test_args entry for TransformationSet (now deprecated).
Properly deprecate TransformationSet.