Revert "Settings: Add HeadsUp setting."

This reverts commit 9b15f9effc1c209082c166bdffbd3422c9f3d1ea.
Revert "Other fix for HeadsUp settings"

This reverts commit 4d4e10f3cf93015e09ee75d24ad28e50586b4257.
Revert "More fixes for HeadsUp"

This reverts commit 249dfcd2388a7492e74ee95881476bc44673255d.
Revert "Changed position for SystemSettingSwitchPreference"

This reverts commit a77a14354160d4c56378000cb3d5f13b93f851ab.
Revert "Settings: Add heads up blacklist options. (2/2)"

This reverts commit 5fb3a9657e45605e2a52fc4d3863bfa78d0d4921.