From Fabien Lavignotte,"Some other litte changes just to clean up the API.

TimeLine : remove virtual inheritance that is not needed
RigGeometry : put some methods/members in private section (everything was public), use META_Object macro
osganimationskinning.cpp : remove two lines that are not needed"

Merged from svn/trunk:

svn merge -r 9736:9737 http://www.openscenegraph.org/svn/osg/OpenSceneGraph/trunk

include/osgAnimation/Timeline

@@ -27,11 +27,11 @@
 namespace osgAnimation
 {
 
-    class Action : public virtual osg::Object
+    class Action : public osg::Object
     {
     public:
 
-        class Callback : public virtual osg::Object
+        class Callback : public osg::Object
         {
         public:
             Callback(){}
@@ -162,7 +162,7 @@ namespace osgAnimation
     };
 
 
-    class Timeline : public virtual osg::Object
+    class Timeline : public osg::Object
     {
     protected:
         typedef std::pair<unsigned int, osg::ref_ptr<Action> > FrameAction;