Fix pointerEvent bug;

Copy from hammerjs#1085

Author: zhouzhongyuan

src/input/mouse.js

@@ -29,6 +29,7 @@ export default class MouseInput extends Input {
     this.evWin = MOUSE_WINDOW_EVENTS;
 
     this.pressed = false; // mousedown state
+    this.init();
   }
 
   /**

src/input/pointerevent.js

@@ -47,7 +47,7 @@ export default class PointerEventInput extends Input {
     super(...arguments);
     this.evEl = POINTER_ELEMENT_EVENTS;
     this.evWin = POINTER_WINDOW_EVENTS;
-
+    this.init();
     this.store = (this.manager.session.pointerEvents = []);
   }
 

src/input/singletouch.js

@@ -33,6 +33,7 @@ export default class SingleTouchInput extends Input {
     this.started = false;
 
     Input.apply(this, arguments);
+    this.init();
   }
 
   handler(ev) {

src/input/touch.js

@@ -34,6 +34,7 @@ export default class TouchInput extends Input {
 
     this.evTarget = TOUCH_TARGET_EVENTS;
     this.targetIds = {};
+    this.init();
   }
 
   handler(ev) {

src/input/touchmouse.js

@@ -27,7 +27,7 @@ const DEDUP_DISTANCE = 25;
 export default class TouchMouseInput extends Input {
   constructor() {
     super(...arguments);
-
+    this.init();
     let handler = bindFn(this.handler, this);
     this.touch = new TouchInput(this.manager, handler);
     this.mouse = new MouseInput(this.manager, handler);

src/inputjs/input-constructor.js

@@ -26,9 +26,6 @@ export default class Input {
         self.handler(ev);
       }
     };
-
-    this.init();
-
   }
   /**
    * @private