TextButtonPanel allows the user to easily add Text/CSS buttons to the map that are styled like the zoom control.  This is a single commit containing of all the changes for TextButtonPanel.  I deleted the original TextButtonPanel branch, as I borked it.
remote unneeded createControlMarkup method
Merge pull request #960 from adv-isu/TextButtonPanel2

TextButtonPanel, Attempt 2 (Zoom-Control-like text+CSS buttons)