dev/david/check_alarms branch
Merge remote-tracking branch 'remotes/origin/dev/david/check_alarms' into dev/patrick/check_alarms
Added a sent field to the alarm content type

- added an integer/boolean field that will track if the text for
  an alarm has been sent yet. It's value will be 1 if sent, 0
  otherwise.
Added controls to prevent resending alarms

- Removed old measures to acheive the same task; they did not appear
  to work and were based on the user rather than the alarm. Also, it
  depended on keeping and searching through a log of users sent to.
  This increases the computational complexity a bit, and also raises
  the question of when such a log should be cleared.
- Used the field_sent field of the alarm content type in order to
  track whether a given alarm has been sent or not. This way
  we eliminate the need to track users.
Added the automatic sending functionality

- Moved the functional code from check_alarms_form_submit() to
  check_alarms() so that it could be called by the cron hook.
- Added Elysia Cron and other missed modules to the install profile
- updated tokens module to use the newest version
- NOTE: crontab has to be set up on the server.
Changed to send a question instead of timestamp
Added message filtering by question type.

- Added a subject and difficulty field to the alarms, consisting
  of term references
- filtered the question asked by subject and difficulty to match
  the subject and difficulty stated in the alarm.
Fixed install profile to include twilio library