lpbin: Add signal handler

Add Handling signals from uridecodebin in lpbin.

Change-Id: If21a211ba4a413e0fdbe80b651bad08767de6fca
Reviewed-on: https://gpro.palm.com/3602
Tested-by: HoonHee Lee <hoonhee.lee@lge.com>
Reviewed-by: Jeongseok Kim <jeongseok.kim@lge.com>
lpbin: Add autoplug sinals handler

Handling autoplug signals from uridecodebin and emit these signals for mediapipeline.

Change-Id: I336b96d86e6328dcae2a66c872d10119aaae9f9c
Reviewed-on: https://gpro.palm.com/4127
Tested-by: HoonHee Lee <hoonhee.lee@lge.com>
Reviewed-by: Jeongseok Kim <jeongseok.kim@lge.com>
lpsink: Change default audio sink

DCO-1.0-Signed-off-by: Jeongseok Kim <jeongseok.kim@lge.com>

Change-Id: I8f7e0cf083dbfd7c4c162478e57fdfed483396cb
Reviewed-on: https://gpro.palm.com/4372
Reviewed-by: Jeongseok Kim <jeongseok.kim@lge.com>
Tested-by: Jeongseok Kim <jeongseok.kim@lge.com>