Port PEEK from PA [1/2]

Sensors are fully disabled when screen is on. When you turn the screen off,
it will start polling both gyroscope and proximity sensor values. If it detects
using the gyroscope sensor that device is lying on a table, it disables proximity
polling. If it detects with proximity sensor that it is in your pocket, it disables
gyroscope polling. This way, we save some battery from the beginning. Later, when you
receive a notification, it enables a partial wakelock (CPU on but at low frequency),
and starts listening for movement, either from getting it out your pocket or lifting
off from the table. If it detects those events, it will turn on screen and show the notification.
Wakelock timeouts on 10 secs, so if you receive a notification and there is no movement in that time,
sensors will stop polling after that time, disabling peek interaction until a new notification comes.
Peek doesn't process low and min priority notifications.

https://plus.google.com/+ParanoidAndroidCorner/posts/3wppxakBSVR

Contributors:
@D4rKn3sSyS
@Anu6is
@BigBrother1984

Signed-off-by: Jesus David <jesdga95@gmail.com>
Signed-off-by: Curtis Mayers <curtis.mayers@gmail.com>
Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>

Conflicts:
	packages/SystemUI/res/values/pa_dimens.xml
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java