accordion: using it on tr elements

[blop@…]

if you're using the accorion plugin with <tr> as headers, it does not work because you click on a <td> or <th> instead of the real header (<tr>)

this fixes this problem:

//if target is not header, get parent
if( !clicked.is(settings.header))
    clicked = clicked.parents(settings.header);

inserted before the if(running ...) check

[joern]

Fixed in latest revision.