Added beginnings of new osgUI library, a replacement for osgWidget that works fully in 3D/stereo and is scriptable.
From Farshid Lashkari, "As discussed, I've added the ability to handle Drawable objects within the NodeVisitor class. Here is an overview of the changes:

- Added apply(Drawable) and apply(Geometry) to NodeVisitor

- Added accept(NodeVisitor) method to Drawable/Geometry

- Added traverse(NodeVisitor) to Geode which calls accept(NodeVisitor) on all Drawables

- Updated CullVisitor to use new apply(Drawable) to handle drawables. The apply(Billboard) method still manually handles the drawables since it is depends on the billboard settings. I needed to disable the traverse within billboard to prevent duplicate traversal of drawables.

- Update other osgUtil node visitors (GLObjectsVisitor, IncrementalCompileOperation, ..) to use new apply(Drawable) method.
"
Changed the Node::ParentList to be a list of osg::Node rather than osg::Group, and added addChild, removeChild, replaceChild virtual method to Node to enable code
to user code compile with minimal modifications to account for the new change to the Node ParentList.
Cleaned up code
Further work on Bound class/Node::getBound() and Drawable::getBound() and usage in OSG codebase
Fixed the bounding sphere computation and handling of Drawable as the root of the scene graph
Added Node::asDrawable() and Node::asGeometry() methods to provide a low cost way of casting a node to Drawable and Geoemtry.

Changed the Group::computeBound() method so that it takes account of the a Drawable's BoundingBox.
Placed the #include<osg/Node> within #ifdef OSG_USE_BOUND to prevent unncessary inclusion of Node header when OSG_USE_BOUND is false.
Added osgGA dependency
From Pjotr Svetachov, build fixes for VisualStudio
From Sebastian Messerschmidt, "There was some small error due to MS non-conformity handling comments correctly."
Added support for intesecting Drawable that are attached directly to the scene graph without an osg::Geode
Added initial shell of PushButton implementation
Added initial cut of ComboBox
Added handling of up/down key to ComboBox
Add shell of Dialog class
Added check against whether an event has been handled or not before actioning escape/quit.
Added shell of Popup class
Improved the handling of updating of text