gobject-2.0: Add GBinding bindings
gobject-2.0: Add GBinding bindings

Based on patch by Gregor Burger, fixes bug 629791.

GNOME/vala,playya/vala,jessevdk/vala,severinh/vala,rvu95/vala,tjol/vala-tjol,spidermonkdust/vala,rvu95/vala,playya/vala,frida/vala,frida/vala,tjol/vala-tjol,kamanashisroy/aroop,playya/vala,Distrotech/vala,severinh/vala,flobrosch/vala-fixes,kamanashisroy/aroop,jessevdk/vala,frida/vala,spidermonkdust/vala,severinh/vala,flobrosch/vala-fixes,jessevdk/vala,Distrotech/vala,frida/vala,GNOME/vala,kamanashisroy/aroop,frida/vala,GNOME/vala,GNOME/vala,xdave/pvala,rvu95/vala,tjol/vala-tjol,flobrosch/vala-fixes,spidermonkdust/vala,Distrotech/vala