Remove limiting of width in session/new

This makes mobile look really bad.
Allow multiple pages to have sort index of nil
No need to use to_s with Rails 4.1
Do not nilify content
This feels more right
Upgrade to Rails 4.1
Switch User admin to role

We are going to use an enum here.
Move nilify_blanks call
Switch to using role as an enum instead of admin as a boolean
Remove whitespace
Ensure that a Membership has a user and team
Admins cannot join teams
Fix max of four users validation
Rename validation, remove team member count
Fix validations for Membership

These need to only be run on :create, as if they are run on :update it
messes stuff up.
No need to filter out this membership

This will not be run on :update, so that is not needed.
Merge branch 'master' into final

Conflicts:
	db/schema.rb