Major rework of basic game code - pre-work for multiplayer

Includes automatic generation of required HTML elements and better responsiveness

js/tetris-manager.js

@@ -0,0 +1,56 @@
+class TetrisManager {
+
+    constructor() {
+        this.container = document.querySelector('.game-container');
+
+        this.instances = new Set;
+    }
+
+    createPlayer() {
+        const game = new Game();
+        this.instances.add(game);
+    }
+
+    init() {
+        this.callAll('rescale', []);
+    }
+
+    removePlayer(tetris) {
+        this.instances.delete(tetris);
+    }
+
+    start() {
+        this.instances.forEach(instance => {
+            instance.start();
+        });
+        this.init();
+    }
+
+    resume() {
+        this.instances.forEach(instance => {
+            instance.g.isPaused = false;
+            instance.g.lastTimeUpdate = Date.now();
+            if (!firstRun) {
+                instance.update(instance.g.lastTime);
+            }
+        });
+    }
+
+    pause() {
+        this.instances.forEach(instance => {
+            instance.g.isPaused = true;
+        });
+    }
+
+    callAll(method, args) {
+        if (typeof method === 'string') {
+            this.instances.forEach(instance => {
+                instance[method](...args);
+            });
+        } else if (typeof method === 'function') {
+            this.instances.forEach(instance => {
+                method(instance);
+            });
+        }
+    }
+}