[WIP] Replace table based panes (build queue, build executors, build history) with a div based approach

This is a WIP.

Trying to replace the current `<l:pane>` based panels with `<div>` based alternatives:

1.  Created a new set of tags (`<l:divpane>`, `<l:divpaneRow>` and `<l:divpaneCell>`) to replace the current `<l:pane>` tag.
2.  Updated the Build Queue, Executors and History panes to use this approach.
3.  Can see it here: http://166.78.9.27:8080/

Intentionally looks similar to current pane but I'm hoping it will work better with new layout.

Looking for people to let me know what they think of this and what issues they foresee.
Adding "td" here makes this much much slower and doesn't help much unless there are multiple different HTML elements with class "executor-name"