Do not use a GString when parsing cdata
Do not use a GString when parsing cdata

This speeds up parsing by ~10%.

mitya57/appstream-glib,hughsie/appstream-glib,ikeydoherty/appstream-glib,ximion/appstream-glib,ximion/appstream-glib,superm1/appstream-glib,kalev/appstream-glib,ximion/appstream-glib,hughsie/appstream-glib,kalev/appstream-glib,superm1/appstream-glib,mitya57/appstream-glib,hughsie/appstream-glib,ikeydoherty/appstream-glib