Fix derp
SlimRecents: Rework show top most task feature

recently introduced this feature needed a bit rework. Basic changes

- do not call settings provider on every preload to prevent high IO work.
  Use our observer for that
- Use internal flag logic to mark topmost task
- Move interpretation of the expanded state into the card
- Due that topmost task is always collapsed do not show expanded icon at all
- Minor cleanup

PS:
- set mFirstTask to null if it is not used

Change-Id: Ifaabc035b6b9bd2d4527d5b34a1bca9c80a74e32
FB: Slimrecents background color && transparency [2/2]

PS: now setting sticks through reboots and TRDS state
        changes. also, add reset to default color option.

PS: when resetting to default, use TRDS (png) resources
        instead of custom color

PS: okay, should be good to go now  :D

Change-Id: Icf0259ce45d416364d6e7a7a8c2038f6c4c0cbde