Add data pipe for signaling only real user activity

Triggered on actual - non synthesized - power key, double tap
and touch screen events.

The data pipe is used only for triggering, no data is passed
through.
Add support for led patterns that auto-disable on display on

LED patterns configured to use policy=6, will be visible only when
the display is off, and will automatically de-activated when the
display is turned on due to direct activity by the user.

[mce] Add support for led patterns that auto-disable on display on
Communication LED patterns use auto-disable policy

Missed call, SMS etc led patterns are de-activated when the user
unblanks the display device via power key or double tap.

[mce] Communication LED patterns use auto-disable policy
Merge pull request #108 from spiiroin/type_6_led

Add support for led patterns that auto-disable on display on