multiplayer fixes

src/input.js

@@ -1,4 +1,4 @@
-import {DEFAULT_KEYPRESS_DELAY, Z} from './constants.js?v=21';
+import {DEFAULT_KEYPRESS_DELAY, Z} from './constants.js?v=22';
 
 const input = {};
 let lastKeypressTime = 0;
@@ -14,6 +14,10 @@ export function key(key) {
   return input[key]
 }
 
+export function clearKeys() {
+  for (const k in input) input[k] = false;
+}
+
 export function afterKeyDelay(amount=DEFAULT_KEYPRESS_DELAY) {
   const now = Date.now();
   if (now - lastKeypressTime >= amount) {