User admin edge cases

[aaronaverill]

1. A user should not be able to delete the last admin in the system.
2. A user should not be able to update a user by unchecking admin if there is only one admin.

Logically, since only an admin can do these operations, they would be taking place on their own account, but its besides the point.

1. If a user deletes their own account the system needs to perform a signout also. Just make sure they aren't around still