Use actual lua functions for callbacks instead of strings

cmd/micro/micro.go

@@ -312,7 +312,7 @@ func main() {
 		select {
 		case f := <-shell.Jobs:
 			// If a new job has finished while running in the background we should execute the callback
-			f.Function(f.Output, f.Args...)
+			f.Function(f.Output, f.Args)
 		case <-config.Autosave:
 			for _, b := range buffer.OpenBuffers {
 				b.Save()