Added deprecation warnings to tests
refine Pow of Abs.
Add a refine_Relational handler.

Allows refine(x < 0, Q.is_true(x<0)) == True
and refine(Piecewise((1, x<0), (3, True)), Q.is_true(x<0)) == 1.
SymPyDeprecationWarnings raise an error in the tests
Merge branch 'master' into deprecation_warning_tests
Fix an import
Merge pull request #2094 from asmeurer/deprecation_warning_tests

Raise an error if SymPyDeprecationWarnings are raised in the tests
Merge pull request #2079 from placasse/refine_Relational

Add a refine_Relational handler.
Merge pull request #1983 from placasse/pow_of_abs

refine Pow of Abs.