Add flash display support
Add BetaInvite to collect e-mails for later use

BetaInvite also has some extra fields for future expandability:

* invite_token - starts out null and is filled in when an invite is sent
to the user that requested it
* user_id      - starts out null and is filled in when an invited user
creates an account (so we know they accepted)
Merge pull request #2 from drewblas/add_beta_invite_form

Add beta invite form [WIP:36]