Add a script to list unpaid teams
Catch errors when trying to find nonexistent teams

Addresses Event ID 8cdc8770bb4e454ea125424985ad73d0
Refactor elo and truskill computation

Less repeated code, less exceptions
Add team eligibility to API
Add permissions classes to codemanagement api
Merge pull request #85 from jonsimington/develop

Use proper bootstrap centering