title: How to call a Model function in Sencha Template
body: <p>I have a client model defined as:</p>
  
  <pre><code>Ext.define('app.model.Client', {
      extend: 'Ext.data.Model',
      alias: 'model.clientmodel',
      fields: [
          {
              name: 'Firstname',
              type: 'string'
          },
          {
              name: 'Lastname',
              type: 'string'
          },
          {
              name: 'Title',
              type: 'string'
          }
      ],
      GetFullName: function(withTitle) {
          var fullName = [this.get('Firstname'), this.get('Lastname')].join(' ');
  
          if(withTitle){
              return [this.get('Title'), fullName].join(' '); 
          }
  
          return fullName;
      }
  });
  </code></pre>
  
  <p>In a grid, I want to have a "Full name" template column - is there a way to call the GetFullName method defined in my Model?</p>
  
  <p>Thanks</p>