add middle mouse binding for ibar exec menu
add middle mouse binding for ibar exec menu

this allows for quick, timer-less, access to the menu

FlorentRevest/Enlightenment,tasn/enlightenment,tasn/enlightenment,rvandegrift/e,FlorentRevest/Enlightenment,tizenorg/platform.upstream.enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,rvandegrift/e,FlorentRevest/Enlightenment