Added history to RequirementModel
Added RequirementModel events getters and setters
fixed priorities and cleaded up RequirementModel code
changing user storage to use id instead of object
continued changes for user storage.
removed pointless code

found out that db4o handles changes across all objects so the changes
in my past commits were not necissary and could possible break
something….
Added numerous comments and documentation. Added list of requirement IDs to a requirement, so that they can be associated with other requirements
added validation classes
Merge remote-tracking branch 'origin/dev' into dev-models
Added comments and refactored list of subrequirements. Added TODO for db4o validation
Merge branch 'dev-models' of github.com:alexhenning/wpi-suite-tng into dev-models
added missing assignee setter to RequirementModel
Merge branch 'dev-models' of github.com:alexhenning/wpi-suite-tng into dev-models
move validator work
RequirementModel validation currently complete

The validation class for the requirement model is currently complete.
corrected a comment error
Change priority enum to HIGH, MEDIUM, LOW, and NONE
Improve the requirement creation panel (e.g., alignment, text area, button, dropdown)
history mangaement
Merge branch 'dev-feature-localmodel' into dev