Begun transition to devise authn

Login works--turns out the old authn system was pretty similar to restful_authentication. Authz does not work at all apart from the "is user logged in or not" kind of way; all logged in users have access to all actions. Logged out users only have access to members/sign_in, events/calendar and events/generate.
Renamed Member.kerbid to Member.email
Fixed editing members
Replaced roles/permissions tables with role field on Member

Note that this commit literally breaks every single page on the website.
Changed display name of email field to "kerbid"
Installed Cancan and wrote basic role abilities
Gave Exec ability to manage attachments and delete comments
Changed login requirement to explicit whitelisting
Protected accounts controller
Protected attachments controller

Attachments can only be deleted from the attachment controller by exec and above--TICs will be able to delete attachments for their event from the event edit page, however.
Protected comments controller

Had to edit events so that the page would load so that I could test comments.
Protected email controller

Also removed dead actions.
Protected form emails controller
Fixed creating accounts and started moving from protected_attributes to strong_parameters
Fixed problem that would prevent server from starting
Strong Parametersized form emails controller
"Protected" equipment controller
Protected events controller

Exec can manage all aspects of an event. An event's TIC can manage all aspects of their event. Someone who has a run position on an event can upload/delete attachments, and modify the notes for an event, as well as remove themself from the run position, and manage the run positions of those who are their assistants (aSM for SM, aME for ME, and so on).

Note that at this point we are disallowing anybody who isn't a tracker dev from deleting events.

refs #91
Added "Treasurer" role
Restricted write access to accounts controller to Treasurers and above