refactor(datepicker): track buttons by date instead of $index

Author: bekos

Diff for: template/datepicker/day.html

@@ -13,7 +13,7 @@
   <tbody>
     <tr ng-repeat="row in rows track by $index">
       <td ng-show="showWeeks" class="text-center"><small><em>{{ weekNumbers[$index] }}</em></small></td>
-      <td ng-repeat="dt in row track by $index" class="text-center">
+      <td ng-repeat="dt in row track by dt.date" class="text-center">
         <button type="button" style="width:100%;" class="btn btn-default btn-sm" ng-class="{'btn-info': dt.selected}" ng-click="select(dt.date)" ng-disabled="dt.disabled"><span ng-class="{'text-muted': dt.secondary, 'text-info': dt.current}">{{dt.label}}</span></button>
       </td>
     </tr>

Diff for: template/datepicker/month.html

@@ -8,7 +8,7 @@
   </thead>
   <tbody>
     <tr ng-repeat="row in rows track by $index">
-      <td ng-repeat="dt in row track by $index" class="text-center">
+      <td ng-repeat="dt in row track by dt.date" class="text-center">
         <button type="button" style="width:100%;" class="btn btn-default" ng-class="{'btn-info': dt.selected}" ng-click="select(dt.date)" ng-disabled="dt.disabled"><span ng-class="{'text-info': dt.current}">{{dt.label}}</span></button>
       </td>
     </tr>

Diff for: template/datepicker/year.html

@@ -8,7 +8,7 @@
   </thead>
   <tbody>
     <tr ng-repeat="row in rows track by $index">
-      <td ng-repeat="dt in row track by $index" class="text-center">
+      <td ng-repeat="dt in row track by dt.date" class="text-center">
         <button type="button" style="width:100%;" class="btn btn-default" ng-class="{'btn-info': dt.selected}" ng-click="select(dt.date)" ng-disabled="dt.disabled"><span ng-class="{'text-info': dt.current}">{{dt.label}}</span></button>
       </td>
     </tr>