Added client-side validation to case type field in the app_manager
The server will now reject any save attempts with invalid case_types.
Additionally, validity is checked by the js directly, and it will add an
error class to the control group, better displaying the problem.  The
input field still has the pattern attribute so the box-shadow
highlighting occurs correctly.
Merge pull request #765 from esoergel/case_type

Added client-side validation to case type field in the app_manager