Django 1.9 Forever

Brings tx_people into the future. Was more concerned with getting it working for tx_salaries than doing anything super relevant to tx_people. Main changes:

• South is no more. Any migrations that run against this will need --fake-initial so Django recognizes that everything is chill.
• Adds some indexing to fields that are killing salaries.texastribune.org right now during updates. We're talking 6 hour updates turning into 45 minute updates with this change.