Refactoring loading of recent apps

- fix bugs 5278690 and 5432097
- no longer forcing a reload when screen is rotated
- moving recents loading code into a seaprate class
- changing variable names to use "Task" rather than "Activity" in Recent Apps

Change-Id: Ib0c8c5d537cf9d46d65b2ccb790015b601bb1bf1
8 files changed