all: [API] deliver events one at a time to allow fine-grained event processing

Processing one event at a time allows a widget to execute commands after
the event that triggered it, instead of after all matching events.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

io/input/router_test.go

@@ -15,7 +15,7 @@ func TestNoFilterAllocs(t *testing.T) {
 		b.ReportAllocs()
 		b.ResetTimer()
 		for i := 0; i < b.N; i++ {
-			s.Events(nil, pointer.Filter{})
+			s.Event(nil, pointer.Filter{})
 		}
 	})
 	if allocs := b.AllocsPerOp(); allocs != 0 {