Add scramble pin layout global setting.

Change-Id: Ic4173a0d65e6bc22ea5ab3061139af12582aac5a
Keyguard: Add option to scramble pin layout when unlocking (2/2).

Change-Id: Ibe8611eb0b8a5bd9275bc96682d2cbafaa37d8f5
Use TYPICAL_PROXIMITY_THRESHOLD instead of mProximitySensor.getMaximumRange()

Presto's proximity sensor returns values: 0.0f(near) or 5.0f(far).
mProximitySensor.getMaximumRange() must return proximity sensor's availible range, but it always return 0, so mProximityThreshold is also 0.

So boolean positive = distance >= 0.0f && distance < mProximityThreshold;  positive will never be
true.
The cause of this problem is proprietary sensor.msm8660.so, it must set proper Range and Resolution for proximity sensor.

Change-Id: Idf23ac50c8ec52bad5fafadbdf8af69dd66c273e