Display Settings: Better font size control

Use a SeekBar instead of a list/spinner to determine the font scaling.
For consistency, an approximate size (small, normal, etc.)
 and the exact percentage are displayed.
Show a preview of the selected font size immediately

Ported from CM 10.2, squashed commits 46678 and 49167.
Credit to Veeti Paaananen for the latter commit.

Change-Id: I754d7fdcaf27c23dfccf9d56291956e70b23f63e
add dslv controller

a lot of our settings have drag swipe features
this is the central controller for it to have
easy access

Change-Id: I9eb9849f2585510649f49c75915b0c7f3c508fdd
Settings: add central slim ActionListViewSettings class back...

as well shortcutpicker helper and several other stuff which is needed
for nearly every feature we have regarding navigation or shortcuts.

Imported from kk

changes:
- Renaming to be inline with fwb part
- code cleanup
- disabled code where features are not present till now

NOTE: This patch from graphics group is needed as well
      https://gerrit.slimroms.net/#/c/19987/2

Change-Id: I7b01e9ff685880c892807a8048aefad5af0c96b1
Settings: materialize grabber icon

Change-Id: I74908674c8d6b5e5f3fbca8e54778c8d9d9dd6b7
Merge remote-tracking branch 'upstream/lp5.0-caf' into lp5.0-caf