[1/3 of 1/2] Base: Smart pulldown

Quickly pulldown quick settings if there are no notifications.
This has 3 modes -
0 - Disabled.
1 - Quick pull down if there are no clearable notifications.
2 - Quick pull down if there are no notifications.

original commit from Utkarsh Gupta for OmniROM (https://gerrit.omnirom.org/#/c/5034/)