Merge pull request #220 from Russell-Jones/master

Add try catch block to test for and use if available new in 1.6 db trans...
Merge branch 'py2and3' of github.com:Russell-Jones/django-wiki into python3
Add six to travis requirements.txt
Try to work around (necessary) absence of force_unicode in Django on python 3
Replace basestring with six.string_types
Import only string_types from six
Start using from __future__ import unicode_literals everywhere
Remove u from  u"" and u''
Start to remove calls to unicode()
Correct position of from future import
Convert filter iterator to list() to allow subscript
Fix #221 - not correctly inheriting some permissions, save() called on URLPath object instead of Article object!
Bump to 0.0.23
Merge branch 'master' into python3
Beginnings of docs - converted from README
Added easy way to brand the wiki, avoiding lots of copy and paste.

Includes docs.
Corrected docs for easy branding method
Merge pull request #227 from spookylukey/easy_branding

Easy branding  + documentation
add rtd conf env
Update .travis.yml
Update requirements_1.6.txt

Add six for Python3 build.
Add python 3.2 and 3.3 to trigger branch tci build