Settings: Adds ability to answer call with hardware HOME button (2/2)

Port of CM commit: f8c9fbcb214f6881ddb6ac02fa5ae45518828be7
Full Credit to CM team

Patchset 2: correcting comment in strings.xml
Patchset 3: fixing total derp of strings.xml

Change-Id: I78336d1fef900eaeeef022914fa80fd920460585