gstreamer: various fixes for 1.0 and cleanups
gstreamer: various fixes for 1.0 and cleanups

always re-create the playbin after the fakeVideo pre-roll to avoid 1.0 issues.
handle the GstVideoOverlay object being created before we get our XID.
set force-aspect-ratio to allow user scaling un-conditionally

Change-Id: I8892b8f7a125c0daa7101e28f274bff3de57ee08

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core