Don't die on an IPv6 IP address

Reviewers: jeff, tail, ted

Reviewed By: ted

Differential Revision: http://phabricator.local.disqus.net/D5113
Add two management commands: add_switch and remove_switch.
Merge pull request #65 from absoludity/master

Basic command-line API
Fix the checks for key and label length

The schema supports 64 char keys and labels but the UI still had limits
of 32. This ups the limits in the UI
Merge pull request #67 from mixcloud/key_length_checks

Fix the checks for key and label length
Bind django-jsonfield to < 0.9.4 (fixes GH-68)
0.10.7
Don't re-use key variable when updating a switch through Nexus.