Added RequirementValidator, which can be used to ensure validity on requirements being pushed to the server. Modeled after DefectValidator.
Removed some unnecessary (for now) database references from entity manager and validator. Validator now initializes requirement type (if null) and status, and handles null linked lists. Added tests for Validator.
Copied over Mock Network/Data/Request types from Defect Tracker. Added session requirements back into validator to support future session/database validation requirements.
Added back in more removed validator functionality.