fix(ngc): _onDragStart/End are called with one param

Fixes #1112

Author: alexeagle

src/lib/slide-toggle/slide-toggle.html

@@ -4,9 +4,9 @@
     <div class="md-slide-toggle-bar"></div>
 
     <div class="md-slide-toggle-thumb-container"
-         (slidestart)="_onDragStart($event)"
+         (slidestart)="_onDragStart()"
          (slide)="_onDrag($event)"
-         (slideend)="_onDragEnd($event)">
+         (slideend)="_onDragEnd()">
 
       <div class="md-slide-toggle-thumb">
         <div class="md-ink-ripple"></div>