python3: replace deprecated <> by !=
Merge branch 'develop' of git://github.com/sagemath/sage into py3_ne
Comparison with `None` using `is` or `is not`.
Trac #13441: refactored gcd to not use _gcd calls anymore
replace "&" by "and"
Trac #13628: refactored xgcd to not use _xgcd calls anymore.
Merge branch 'u/niles/ticket/13441' of trac.sagemath.org:sage into u/tscrim/ticket/13441

* 'u/niles/ticket/13441' of trac.sagemath.org:sage:
  Trac #13441: refactored gcd to not use _gcd calls anymore
Removed tab characters and some very minor review tweaks.
Merge branch 'u/niles/ticket/13628' of trac.sagemath.org:sage into u/tscrim/ticket/13628

* 'u/niles/ticket/13628' of trac.sagemath.org:sage:
  Trac #13628: refactored xgcd to not use _xgcd calls anymore.

Conflicts:
	src/sage/rings/polynomial/polynomial_quotient_ring.py
Some minor docstring review changes.
Fixed failing doctests.
Fixed missed parenthesis for a tuple.
Fix typo and MATH docstrong.
Trac #15734: <> is not Python 3 compatible

Replace {{{<>}}} by {{{!=}}}.

URL: http://trac.sagemath.org/15734
Reported by: aapitzsch
Ticket author(s): André Apitzsch
Reviewer(s): Jeroen Demeyer
Trac #13441: refactor gcd

Currently, some classes define a {{{_gcd}}} method which is called by a
{{{gcd}}} method of euclidean domain elements. Most elements already
define {{{gcd}}} directly, and I see no real use in having this method
in between.

The attached patch renames all {{{_gcd}}} methods to {{{gcd}}} and also
streamlines the use of {{{@coerce_binop}}} on them.

This is similar to #13628.

URL: http://trac.sagemath.org/13441
Reported by: saraedum
Ticket author(s): Julian Rueth
Reviewer(s): Niles Johnson, Travis Scrimshaw
Trac #13628: refactor xgcd

Currently, some classes define a _xgcd method which is called by a xgcd
method of euclidean domain elements. Most elements already define xgcd
directly, and I see no real use in having this method in between.

The attached patch renames all _xgcd methods to xgcd and also
streamlines the use of @coerce_binop on them.

This is similar to #13441.

URL: http://trac.sagemath.org/13628
Reported by: saraedum
Ticket author(s): Julian Rueth
Reviewer(s): Niles Johnson, Travis Scrimshaw