<> is not Python 3 compatible

[aapitzsch]

Replace <> by !=.

[aapitzsch]

New commits:

​0b286ea

python3: replace deprecated <> by !=

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​90e394a

Merge branch 'develop' of git://github.com/sagemath/sage into py3_ne

[Jeroen Demeyer]

Comparisons with None should be done using is or is not.

[Jeroen Demeyer]

Also, conditions like

if ((a==t) & (s<>0)):

should be replaced by

if a == t and s != 0:

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​12c89cf	Comparison with `None` using `is` or `is not`.
​1e018de	replace "&" by "and"