Use sqrt_mod() from Pernici's work
Skip the test in test_failing_integrals that is too slow for @slow

This test never finishes (or at least, it would probably take days), so
without a timeout, the slow tests don't complete. This was causing the slow
tests to timeout in the NiPy buildbot
(http://nipy.bic.berkeley.edu/builders/sympy-py2.6-32/builds/0/steps/shell_4/logs/stdio).
Merge branch 'master' into preview_bytesio

Conflicts:
	sympy/interactive/printing.py
Merge pull request #2417 from asmeurer/travis-sage

Run Sage tests in Travis
Merge pull request #2314 from skirpichev/unxfail-wester-H3

UnXFAIL Wester test H3
sqrt_mod() used
some more comments
Add some more tests.
A couple small fixups.
Use \, to separate the integration variable.
Whitespace fixes.
Doctests fixed
Made the changes proposed by Stephen
Merge master
Merge pull request #2365 from katjasophie/modgcd_funcfield

Modular GCD for polynomials over algebraic number fields
Use ntheory primitive_root
Fixed overflow bugs in ``_sqrt_mod1``
Mention ask_update.py in docstring of compute_known_facts()
Move logic out of sympy/assumptions/handlers/__init__.py
Use CommonHandler's AlwaysTrue/AlwaysFalse