Report error when declaring signals with static modifier
Report error when declaring signals with static modifier

Fixes bug 594440.

rvu95/vala,GNOME/vala,kamanashisroy/aroop,Distrotech/vala,lovebug356/vala,phako/vala,frida/vala,themiwi/vala,GNOME/vala,xdave/pvala,frida/vala,frida/vala,kamanashisroy/aroop,jessevdk/vala,GNOME/vala,flobrosch/vala-fixes,Jc2k/vala,flobrosch/vala-fixes,GNOME/vala,spidermonkdust/vala,frida/vala,flobrosch/vala-fixes,playya/vala,frida/vala,phako/vala,severinh/vala,jessevdk/vala,themiwi/vala,playya/vala,severinh/vala,lovebug356/vala,tjol/vala-tjol,spidermonkdust/vala,tjol/vala-tjol,playya/vala,severinh/vala,Distrotech/vala,tjol/vala-tjol,spidermonkdust/vala,Jc2k/vala,kamanashisroy/aroop,themiwi/vala,Distrotech/vala,rvu95/vala,rvu95/vala,jessevdk/vala