Submissions break when not on team

[wflms20110333]

If you try to submit code without officially creating and being on a team, it breaks. Should probably directly disallow submissions when not on teams (official one-man team is ok).

The funny thing is, the submissions tab is not displayed when you're not on a team, but I found the link in Getting Started anyway and unintentionally caught this.

[n8kim1]

(This also applies for scrimmages too, I think)

A quick fix would be to say "make sure you're on a team!", but we should def look into a more robust solution later