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
Improve subs for Derivative.

Perform substitutions if derivative variables are in a different, but
equivalent order and perform substitutions for subderivatives.
Add additional tests for Derivative subs method.
Report test name in case of runtest failure; add missing print_function.

Make runtests.py report the name of a test if an exception is thrown
before it outputs the test name normally. This makes sure that the
name of a test is printed even in the face of runtest machinery failure.

Added a print_function import from __future__ to test_codegen, which
would make tests fail all over the place when --enhance-asserts was
active.
Merge remote-tracking branch 'sympy/master' into derivsubs

Conflicts:
	sympy/core/function.py
Updating classes to use __new__ instead of init
Change preview to use BytesIO instead of StringIO

This fixes it to work in Python 3. Since BytesIO is available in Python 2.6,
the use of StringIO has been deprecated. See
https://code.google.com/p/sympy/issues/detail?id=3984.

This fixes, in particular, init_printing(use_latex='png') in Python 3.
Enable if x.is_positive is branch in series()
Workaround in Function._eval_nseries to prevent some substitutions in the Derivative

    For example: Subs(Derivative(f(x), x), x, 0).subs(x, y) ->
                 Subs(Derivative(f(x), x), (x,), (y,))

    This is a fix for failed test:
    File "/home/sk/src/sympy/sympy/series/tests/test_series.py", line 86, in test_879
      assert f(x).series(x, 0, 3) == \
Less naive lseries/nseries methods for Integral

    Detect cases, when we should expand on the integration
    variable (dummy symbol).
Correct assumptions for auxilary symbol xpos: it should be is_bounded as well