Added method to send out mail about a Task update. Reviewed by: Lennard de Rijk

Added template for mails regarding Task updates. Reviewed by: Lennard de Rijk

Added several methods to the Task Logic module. These include the automatic tranistion methods. The methods for running updates , that for instance place comments, in a datastore transition to keep the Task synced with the comments. And a rudimentary way of updating the Tasks' history. Reviewed by: Lennard de Rijk

Removed scope and scope_path properties from GHOPComment since it is ID based.

Added reference to GHOPProgram entity for Work Submissions.

Added GHOP Form cleaning module. Reviewed by: Lennard de Rijk

Added GHOPTaskSubscription Logic module. Reviewed by: Lennard de Rijk

Added GHOP Student Logic. Note that on creation of a GHOPStudent a GAE Task is created to update the taskswith the new GHOPStudent reference. This is due to the fact that we allow users to claim task without being a registered Student. Reviewed by: Lennard de Rijk

Added GAE tasks that are related to updating GHOP Tasks. Several TODO's have been added. Also note that some functionality that is being used here is under construction and is being integrated asap. That's the price to pay for cleaner integration commits I guess :). Reviewed by: Lennard de Rijk

Added GHOP Logic helper package. Reviewed by: Lennard de Rijk