user_level field doesn't exist on fresh install [patch]

[ringmaster]

On a fresh install, the install.php attempts to set the user level for the first (admin) user, and cannot because that field no longer exists.

The installer should use the new role system.

Patch attached.

[ringmaster]

Patch for installer to support roles.

[ryanduff]

I tested and can confirm that this patch fixes the previous install problems.

[ryan]

(In [2707]) Setup admin's role during install. Props: Owen Winkler. fixes #1505