gst: init taglist gtype to use it in gstvalue
gst: init taglist gtype to use it in gstvalue

Otherwise it will have a 0 value and GstTagList won't be found
for GstValue functions (serialization/deserialization)

https://bugzilla.gnome.org/show_bug.cgi?id=733131

StreamUtils/gstreamer,jpxiong/gstreamer,surround-io/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,centricular/gstreamer,mparis/gstreamer,krichter722/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,mparis/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,mparis/gstreamer,surround-io/gstreamer,surround-io/gstreamer,surround-io/gstreamer,surround-io/gstreamer,mparis/gstreamer,jpxiong/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,krichter722/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,centricular/gstreamer