[GTK][jhbuild] Switch to GStreamer 1.0 build

[GTK][jhbuild] Switch to GStreamer 1.0 build
https://bugs.webkit.org/show_bug.cgi?id=91727

Patch by Xabier Rodriguez Calvar <calvaris@igalia.com> on 2012-12-11
Reviewed by Philippe Normand.

Switch build-webkit --gtk to GStreamer 1.0 support and build the
necessary GStreamer git modules from JHBuild.

.:

* configure.ac: Removed GStreamer unstable API flag, made
GStreamer 1.0 default instead of 0.10 and made required version
1.0.3. In case no GStreamer version is specified, it falls back to
0.10. In case no video or web-audio are requested, GStreamer
and Farstream checks are not performed.

Tools:

* gtk/jhbuild.modules: Added GStreamer 1.0.3 build support.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@137271 268f45cc-cd09-0410-ab3c-d52691b4dbfc