@pzwang, @hhuuggoo, @paddymul how is this syntax for specifying values for the tooltip:
* `$foo` special variables that the tools knows about
* `@name` a column to look up on the data source
plus a special syntax for colors: `$color[hex,swatch]:column_name` where the options in brackets are optional and the column to look up comes last.

For reference here is the output of that table:
![screen shot 2014-02-16 at 11 13 37 am](https://f.cloud.github.com/assets/1078448/2180749/b947e97a-972d-11e3-838d-0f7b7d4078ed.png)