IE8 support (#314)

* IE8 support

IE8 requires the ability to use the alternative directive syntax : <div rzslider ... ></div>

Fixes #313

* Update for new default template

* New template for IE8 support

* Update for new template

* oops

* Suggested fixes for #314

src/rzSliderTpl.html

+<div class="rzslider">
 <span class="rz-bar-wrapper"><span class="rz-bar"></span></span> <!-- // 0 The slider bar -->
 <span class="rz-bar-wrapper">
   <span class="rz-bar rz-selection" ng-style="barStyle"></span>
@@ -20,3 +21,4 @@
     <span ng-if="t.legend != null" class="rz-tick-legend">{{ t.legend }}</span>
   </li>
 </ul>
+</div>

src/rzslider.js

@@ -1903,7 +1903,8 @@
     'use strict';
 
     return {
-      restrict: 'E',
+      restrict: 'AE',
+      replace: true,
       scope: {
         rzSliderModel: '=?',
         rzSliderHigh: '=?',

src/rzslider.less

@@ -8,7 +8,7 @@
  */
 @import 'variables.less';
 
-rzslider {
+.rzslider {
   display: inline-block;
   position: relative;
   height: @barDimension;