[Trinidad] navigationPane::tabs now has doc and demo

[Jeanne Waldman]

Hi there,

I just checked in to trunk the skin selector keys for 
navigationPane::tabs and I added a demo that uses other images besides 
the default in the beach skin.
These tabs look very similar the old 'oracle' skin, so those of you who 
have oracle/redwood shores skins can add these to your skin. You might 
need to fix up the images to make them more perfect looking.

The purple skin has a demo of using background-colors and no 
background-images.

- Jeanne