Allow override of DUN settings

Allow override of system DUN settings by setting
persist.sys.dun.override
to one of the following values:
2 = not set, 0 = DUN not required, 1 = DUN required
If the prop is not set or is set to an invalid value the system setting
will be used.

Conflicts:
	services/java/com/android/server/connectivity/Tethering.java

Change-Id: I296f303a23351e4ab29898895abfcd313c747db9
Turn off some debugs

Change-Id: I60ecc6e834277019f467ab69389d0f3da516b2f4
SlimSeekBarPreference
Revert "Tethering: IPV6 tethering support"

This reverts commit e9db65e48dcfd77a34468aeabc4b338889324ca8.
Revert "Power menu: Change color of volume selector to material green"

This reverts commit b67865b3a864d7af1d37f314e2d747d586fee923.
Revert "Fuck you ShutdownThread: Fix build errors"

This reverts commit c080b75dfc557a4185c758bda1121011cd0946cc.
Revert "Frameworks: Material Blackout"

This reverts commit 79ed914bd6117e79d19785bb7e14af6b763931e3.
Revert "Add reboot menu [1/2]"

This reverts commit be6a568637cb56aed08a2280f68ca5b8881e58ff.