title: Extjs create a grid feature or grid plugin that sets a tooltip for each column in the grid
body: <p>This question has the answer to adding the tooltip: 
  <a href="https://stackoverflow.com/questions/7539006/extjs4-set-tooltip-on-each-column-hover-in-gridpanel">Extjs4 set tooltip on each column hover in gridPanel</a></p>
  
  <p>I have a follow up question to the most upvoted answer to this question, which is modifying the renderer function to add the tool tip like below:</p>
  
  <pre><code>{
      xtype : 'gridcolumn',
      dataIndex : 'status',
      text : 'Status',
      renderer : function(value, metadata) {
                      metadata.tdAttr = 'data-qtip="' + value + '"';
                      return value;
                  }
  }
  </code></pre>
  
  <p>I want to have a grid plugin or feature which sets a custom tooltip using the above implementation. </p>
  
  <p>Question is how can I add my stuff but at the same time not take away a user defined renderer function being used for a particular grid. Essentially I want to add the tooltip feature for all grids, but not take away the ability to specify custom renderers for some columns on some of the grids.</p>
  
  <p>I guess what could be a possible alternative is another less invasive place where I could modify this metadata.tdAttr value. Maybe an event that someone would know about?</p>