Merge pull request #299 from tkliuxing/master

Add Simplified Chinese translation.
Added validation for slugs conflicting with 3rd party URLs, and option to disable with ALLOW_OVERLAPPING_THIRD_PARTY_URL = True
Updated setting name ALLOW_OVERLAPPING_THIRD_PARTY_URL to CHECK_SLUG_URL_AVAILABLE
Merge pull request #300 from pknowles/master

Added validation for slugs conflicting with 3rd party URLs
Update .travis.yml

Correct IRC channel for Travis builds.
Merge pull request #301 from Fantomas42/patch-1

Update .travis.yml
Update installation.rst

Fixed     
`INSTALLED_APPS.append('south')
AttributeError: 'tuple' object has no attribute 'append'
`
Merge pull request #303 from thanhleviet/patch-1

Update installation.rst
Python 3 compatibility (or at least correct syntax) for mediawikimport command
Merge pull request #307 from spookylukey/master

Python 3 compatibility (or at least correct syntax) for mediawikimport c...