Change CommonJS package structure

Instead of making Xterm prototype extending optional, just require Xterm and pass it as parameter to the function just like it is being done with RequireJS

addons/attach/attach.js

@@ -11,7 +11,7 @@
     /*
      * CommonJS environment
      */
-    module.exports = attach.call(this);
+    module.exports = attach(require('../../src/xterm'));
   } else if (typeof define == 'function') {
     /*
      * Require.js is available
@@ -107,43 +107,28 @@
   };
 
   /**
-   * Extends the given terminal prototype with the public methods of this add-on.
+   * Attaches the current terminal to the given socket
    *
-   * @param {function} Xterm - The prototype to be extended.
+   * @param {WebSocket} socket - The socket to attach the current terminal.
+   * @param {boolean} bidirectional - Whether the terminal should send data
+   *                                  to the socket as well.
+   * @param {boolean} buffered - Whether the rendering of incoming data
+   *                             should happen instantly or at a maximum
+   *                             frequency of 1 rendering per 10ms.
    */
-  exports.extendXtermPrototype = function (Xterm) {
-    /**
-     * Attaches the current terminal to the given socket
-     *
-     * @param {WebSocket} socket - The socket to attach the current terminal.
-     * @param {boolean} bidirectional - Whether the terminal should send data
-     *                                  to the socket as well.
-     * @param {boolean} buffered - Whether the rendering of incoming data
-     *                             should happen instantly or at a maximum
-     *                             frequency of 1 rendering per 10ms.
-     */
-    Xterm.prototype.attach = function (socket, bidirectional, buffered) {
-      return exports.attach(this, socket, bidirectional, buffered);
-    };
-
-    /**
-     * Detaches the current terminal from the given socket.
-     *
-     * @param {WebSocket} socket - The socket from which to detach the current
-     *                             terminal.
-     */
-    Xterm.prototype.detach = function (socket) {
-      return exports.detach(this, socket);
-    };
+  Xterm.prototype.attach = function (socket, bidirectional, buffered) {
+    return exports.attach(this, socket, bidirectional, buffered);
   };
 
   /**
-   * If the Xterm parameter is a function, then extend it with the methods declared in this
-   * add-on.
+   * Detaches the current terminal from the given socket.
+   *
+   * @param {WebSocket} socket - The socket from which to detach the current
+   *                             terminal.
    */
-  if (typeof Xterm == 'function') {
-    exports.extendXtermPrototype(Xterm);
-  }
+  Xterm.prototype.detach = function (socket) {
+    return exports.detach(this, socket);
+  };
 
   return exports;
 });