Pie controls: Tweaking UX for pie service (2/2)

This is the Settings application part of the
user settable activation sensitivity patch for pie controls.

For the complete message look at the commit in
frameworks/base.

Patch Set #3:
* Enabled "Very High"
* Changed title from "Sensitivity" to "Responsiveness"
* Display summary

Patch Set #4:
* "Very High" -> "Very high"

Change-Id: I99fbbc94c75b64121fd04ff5deb8f5a10a04a63b