Issues GUI improvements :
-Separated the issues edit/add screens to avoid confusion.
-Added an issues link at top of patient summary in case still
want to see all issues on one screen.
-Added a mechanism to allow selection of none for an issue category.
This is for AMC rulesets. Note that when a user adds first entry or
clicks the None radio button, then a irreversible entry is places in
the lists_touch table. This allows computation of rules that require
use of certain categories (Problems, Meds and Allergies).