From Aurélien Chatelain, "updates the STL plugin:
* fixes vertex color support
* adds 'magics' color definition
* cleans options to make the plugin more consistent with other plugins
* adds options to not tristrip geometries"

Submitted by Marc Helbling.


git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14638 16af8721-9629-0410-8352-f15c8da7e697