Bluff charts types

Hello,

The types 'side_stacked_bar', 'stacked_bar' and 'stacked_area' aren't working because the types are incorrect when you traslates to Bluff's classnames.

At line 27 in charts_bluff.class.inc I changed:

$type = ucfirst($this->type);

to

$type = str_replace(' ', '', ucwords(str_replace('_', ' ', $this->type)));

Maybe yo make a better code.

Thanks for this module! :-)