make scheduler into a crate feature

src/runner/runner.rs

@@ -110,7 +110,7 @@ impl Runnable<'_>{
 		if let Some(threads)=scheduler_mut(&self.lua,|scheduler|Ok(scheduler.tick_threads()))?{
 			for thread in threads{
 				//TODO: return dt and total run time
-				let result=thread.resume::<mlua::MultiValue>((1.0/20.0,0.0))
+				let result=thread.resume::<mlua::MultiValue>((1.0/30.0,0.0))
 					.map_err(|error|Error::Lua{source:"source unavailable".to_owned(),error});
 				match result{
 					Ok(_)=>(),