title: Add attribute to gridcolumn xtype in extjs 4.2
body: <p>I have a grid, and I need to add an attribute to the TD of the grid cell (not the header, the cell in the grid itself). It will probably be the same text at the column header, so I'd like to just define it in the <code>gridcolumn</code> xtype when I'm creating my columns. In doing some research I've found a <code>tdAttrs</code> config which I think would help, but I'm not entirely sure how to implement it. Can anyone offer some pointers? If that's not the right direction to be looking, please let me know as well.</p>
  
  <p>Also, I need this to be added to ALL the <code>gridcolumn</code>s in my application, so would I need to add an override for <code>ext.grid.column.Column</code> or put it somewhere else?</p>