GStreamer: port to 1.0.

0.10 is still used by default.
To enable GStreamer 1.0, pass GST_VERSION=1.0 to qmake
for qtmultimedia.pro.

Contributions from:
Andrew den Exter <andrew.den.exter@qinetic.com.au>
Ilya Smelykh <ilya@videoexpertsgroup.com>
Jim Hodapp <jim.hodapp@canonical.com>
Sergio Schvezov <sergio.schvezov@canonical.com>

Change-Id: I72a46d1170a8794a149bdb5e20767afcc5b7587c
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>