FWB: Custom scrolling values 1/2

ported/modified from https://gerrit.omnirom.org/#/c/4251/
originally written by Yanuar Harry <ai.the.smarties.physics@gmail.com>

AICP:
PS2: fix build
PS3: Use default values as defaults

Change-Id: I7f23fe736507f836137c5d6dc0b5fd2ad4a95462

Conflicts:
	core/java/android/provider/Settings.java
Toast Animations [1/2]

Change-Id: Ib6b5aa94237207ada78c512997c8fc9765d68d1f

Conflicts:
	core/java/android/provider/Settings.java
	core/java/android/widget/Toast.java
	core/res/res/values/symbols.xml