title: md-select search filter working based on ng-value but should work on text
body: <p>I have a md select search filter which have several options.<br>
  For Example:<br>
  id: 133, label:'Route1'<br>
  id: 144, label:'Route2'<br>
  id: 155, label:'Route3'<br>
  id: 166, label:'Route4'<br></p>
  
  <p>If i type 1 on the filter, it should show only the first option, but showing all the option because id field has '1' contained in it.</p>
  
  <p>Sample Code:</p>
  
  <pre><code>  &lt;md-select id="Route" name="Route" ng-model="filter.RouteIds" multiple data-md-container-class="mdSelect" md-on-close="RouteChange();" ng-required="(sellerFilter &amp;&amp; needfilter &amp;&amp; '@routeReq' =='required')"&gt;
                                                      &lt;md-select-header class="mdSelectHeader"&gt;
                                                          &lt;input ng-model="SearchRoute"
                                                                 type="search"
                                                                 placeholder="@Misc.getResource("APP_CMN_LBL_Search")"
                                                                 class="mdSelectSearchBox md-text"&gt;
                                                      &lt;/md-select-header&gt;
                                                      &lt;md-button style="width: 93%;text-align: left;font-size: 12px;" value="all" ng-click="fnSelectAllRoute()"&gt;{{routeToggleText}}&lt;/md-button&gt;
                                                      &lt;md-option ng-repeat="route in routes | filter: SearchRoute" value="{{route.value}}" ng-mousemove="fnCheckToggleText(filter.RouteIds.length, routes.length, 'routeToggle');"&gt;
                                                          {{route.label}}
                                                      &lt;/md-option&gt;
                                                  &lt;/md-select&gt;
  </code></pre>