add support for algebraic functions in minpoly
fix test failures
add tests for minpoly over fraction fields
Fix bug in _choose_factor
minpoly: check that the variable is not contained in the ground domain
minpoly: fix test failures
minpoly: add support for algebraic extensions of QQ
minpoly: update documentation

also rename _minpoly_op_algebraic_number to _minpoly_op_algebraic_element
and update error messages
minpoly: add more tests
minpoly: fix doctest error
Merge branch 'master' into AlgebraicDomain

Conflicts:
	sympy/polys/numberfields.py
	sympy/polys/tests/test_numberfields.py
minpoly: use dom.symbols instead of dom.gens

to determine whether a variable or expression is contained in the ground domain
minpoly: minor changes

-) use floor operator instead of converting to int
-) use c.is_negative istead of c < 0
-) remove unnecessary line
minpoly: substitute ground variables before outside evalf
minpoly: make _invertx and _muly more readable
Merge branch 'master' into AlgebraicDomain
minpoly: add a test
minpoly: use rational numbers instead of floats in _choose_factor
minpoly: don't use integrate in test_numberfields
Merge pull request #2128 from katjasophie/AlgebraicDomain

Add support for function fields in minpoly