girparser: Add constructor to boxed types.
girparser: Add constructor to boxed types.

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