Improvements in problem lists for MU2.

1) Added a new field "modifydate" in table "lists" which
   will be updated each time the medication is updated.
2) Added new field "ct_problem" in the table "code_types"
   for setting the code types to be displayed while
   adding a "Medical Problem".
3) Made modifications in Add/Edit issue interface to list
   the code types set as "ct_problem".

Signed-off-by: vinish <vinish@zhservices.com>
Integrating the problem list improvements with the recent fee sheet improvements, take 3.
incremented version database for previous commit