Use .on/.off for event binding, thanks @ayumihamsaki

Closes #201

Author: dmethvin

jquery.mousewheel.js

@@ -84,11 +84,11 @@
 
     $.fn.extend( {
         mousewheel: function( fn ) {
-            return fn ? this.bind( "mousewheel", fn ) : this.trigger( "mousewheel" );
+            return fn ? this.on( "mousewheel", fn ) : this.trigger( "mousewheel" );
         },
 
         unmousewheel: function( fn ) {
-            return this.unbind( "mousewheel", fn );
+            return this.off( "mousewheel", fn );
         }
     } );
 

jquery.mousewheel.min.js

@@ -30,7 +30,11 @@ QUnit.test( ".mousewheel() shorthand", function( assert ) {
     markup.mousewheel( function( e ) {
         assert.ok( true, "triggered a mousewheel event on " + e.target.innerText );
     } );
-    markup.trigger( "mousewheel" );
+    markup.mousewheel();
+
+    // Should not trigger another event
+    markup.unmousewheel();
+    markup.mousewheel();
 
     markup.remove();
 } );