Add support for monitor hotplug detection.

Add a udev rule file and script to run monitor_reconfigure instead
of requiring the user to hit Ctrl-Fullscreen (Ctrl-F4, was Ctrl-Alt-M)
to enter/exit Presentation Mode.

BUG=chromium-os:3107
TEST=Plug in/out external monitor and wait a few seconds of reconfiguration.

Change-Id: I222998d64e4b94cd648085fdd70ad5daad48c7af

Review URL: http://codereview.chromium.org/5637002
2 files changed