title: ng-click not working from ui-grid checkbox cellTemplate
body: <p>I searched a lot around this problem but didn't get any solution which is actually working out to fulfill my needs.
  Problem: I wanted to select the row entity on clicking of the checkbox having a columnDef as  <code>[{name: 'field01', displayName: '', field: 'field01', cellTemplate: "&lt;input type='checkbox' ng-model='row.entity.field01' ng-click='grid.appScope.myhello()' /&gt;"}</code>].</p>
  
  <p>I am building this columnDef dynamically based on another JSON [Updating Working Code]</p>
  
  <pre><code>  $scope.columnDef = function(){
      var column = [{name: 'field01', displayName: '', field: 'field01', cellTemplate: "&lt;input type='checkbox' ng-model='row.entity.field01' ng-click='grid.appScope.myhello(\"row.entity.field01\")' /&gt;"}], coltype = [];
      angular.forEach($scope.columns, function(value, index){
        coltype = [];
        switch(value.type){
          case "Number":  coltype.push({type: "number"});
                          break;
          case "String":  break;
          case "Boolean": coltype.push({editableCellTemplate: "ui-grid/dropdownEditor", cellFilter: "mapBool", editDropdownValueLabel: "bool", editDropdownOptionsArray: [{ id: 1, bool: 'Yes' },{ id: 2, bool: 'No' }] });
                          break;
          case "Date":    coltype.push({type: 'date', cellFilter: 'date:"MM/dd/yyyy"'});
                          break;                  
        }
        column.push(angular.extend({name: value.name, displayName: value.name, enableCellEdit: (value.edit.indexOf("No") != -1) ? false : true}, coltype[0]));
      });
  
      return column;
    };
  
    $scope.gridOptions.data = $scope.datagrid;
    $scope.gridOptions.columnDefs = $scope.columnDef();
  
    $scope.myhello = function(value){
      console.log("It works!!! :-) " + value);
    };
  </code></pre>
  
  <p>The above code updates the datagrid JSON of the field01 but it don't call the ng-click function. I referenced two Plunkr one with external-scope in ui-grid <a href="http://plnkr.co/edit/Gw3eb89IJJIezg4coljb?p=preview" rel="nofollow">Plunkr</a> and another one with defining a method in gridoptions and call it locally <a href="http://plnkr.co/edit/hgTQ1XdEVRyxscoNs76q?p=preview" rel="nofollow">Plunkr</a> (In this plunker the ng-click is getting called but when I tried checking the value inside the editUser function it was not working as expected).</p>