Spring 2013 CAN updates

Includes the following major updates, as well as many minor enhancements and bug fixes:

Upgrades to Rails 2.3.18 and switches to mysql2 gem.

New models and associated application components: Parent, TestScore, TestType, ClearinghouseRecord, Customer, MentorTermGroup, MentorTerm, Term, CollegeEnrollment, CollegeDegree, GradeLevel.

Adds Customer scoping and multi-tenency foundation. DreamSIS is no longer dependent on UW systems and business processes, and customers can customize labels and settings that are different from the UW preferences. This includes changing Quarter to Term (and associated models like MentorQuarterGroup).

Adds a generic RestfulController for simple controllers that don't need to be customized, so that the code will be DRYer.

Adds National Student Clearinghouse processing and enhanced mentor management, including incorporating Mandrill for sending transactional emails to users.