Prevent robots that haven't weighed in from competing

[robertcampion]

Right now there is a field in the database, editable from the teams page, that stores whether a team's robot has been checked in and weighed.

However, this field really has no effect. I'd like to add:

• A warning flag next to the team name in the games page for a team that hasn't weighed in.
• A highly visible warning in the judging interface.