Begins validating date for deadline

Validating user entered date for deadline, and making sure it is not in
the past. Not fully functional with errors in the save button being
enabled or not.

Authors: dbtrue, ammesonb
Merge branch 'team9dev' into validate-deadline
Finishes validating date for deadline

Fixed bugs with save button. Button now grays out and enables at
appropriate times.

Author: dbtrue
Formatting and comments

Fixing formatting and adding some comments.

Author: dbtrue
Automatically select newly entered requirement

Selects new requirement in new game panel when the requirement is saved.

Authors: dbtrue, ammesonb
Disables save button on attempt with invalid date

Previously save button was not disabled if deadline was valid when entered
but not when save is clicked.

Author: dbtrue, ammesonb
Merge pull request #48 from dbeckwith/validate-deadline

Validate deadline