Key forwarding and single app mode update

Added key forwarding for keyboard keys and navigation buttons.
Navigation bar now unhidden on video activity (now hidden on VM).
Fixed bug where receiving a DIAL intent from the VM would cause
non-telephony-enabled devices to crash.
Changed receiving DIAL intents to trigger a CALL action instead.
Added preference to use Desktop Mode, false by default (now Single
App Mode is used by default).
Fixed navigation issues when entering the SVMP Client via a
notification.
Changed Apps Refresh Request message, now excludes the Icon Hash if
it is null (instead of sending an empty ByteArray).
Added ConfigHandler to send a Request message when a hardware
keyboard is attached.
Added extra SDK checks/failsafes when building Notifications.
Separated NetIntents handler into IntentHandler and
NotificationHandler.

Co-commits:
android_device_mitre_svmp
android_external_svmp_eventserver
android_frameworks_base
svmp-protocol-def
svmp-server