Adds pytz-2014.4.tar.gz

Dependency of Babel.

Change-Id: I38813f80f2bf43d24ce1206fccd54160212934f1
Merge branch 'dependencies' into master

Adjust requirements.txt to point to the tarballs of:
- PrettyTable
- six
- Babel
  - pytz

Change-Id: I7c76c76f5b2e213b7ea71a3ab019cb7a895b50a8