Testing improvements
- created a helper class PriorityTestSetUp to extend GroovyTestCase and include common priority data
- changed priority integration tests to extend PriorityTestSetUp
- created package edu.harvard.cscie56.prektest and moved tests under the directory structure
- changed all priority tests to create a school and pass school as parameter to the  PriorityOverride constructor
- PersonalInfoTests.groovy moved under new package
- removed all auto-generated tests that do nothing