overflow-scroll fix

https://github.com/oori/ionic/commit/9460d9bdd4a4aed64572b58c75e47117ba5eb2c3 Removes duplicates
https://github.com/oori/ionic/commit/0a9b7c2cabef91e38891e6196689dbc59ba0d545 Handles a well-known iOS scrolling issue (disappearing items on scrolling)