remove transifex-client from dev requirements file as it does not work on python 3.4

add a note to docs about transifex-client installation and python version issues.
Merge remote-tracking branch 'origin/master'
Merge pull request #191 from elnappo/master

add python 3 compatibility and some minor stuff
catch IndexError when computing IP of related hosts, fixes #190
New layout for user area (change password, delete acc, change profil)
Merge branch 'master' of github.com:nsupdate-info/nsupdate.info