added float *() operator to Vec{2,3,4} so we can pass Vec3's directly to

OpenGL glVertex?fv().

include/osg/Vec2

@@ -148,6 +148,8 @@ class Vec2
 	    return( norm );
 	}
 
+        inline operator float * (void) { return _v; }
+
 	friend inline ostream& operator << (ostream& output, const Vec2& vec)
         {
 	    output << vec._v[0] << " "

include/osg/Vec3

@@ -167,6 +167,8 @@ class Vec3
             return( norm );
         }
 
+        inline operator float * (void) { return _v; }
+
 	friend inline ostream& operator << (ostream& output, const Vec3& vec);
 
 };	// end of class Vec3

include/osg/Vec4

@@ -178,6 +178,8 @@ class Vec4
             return( norm );
         }
 
+        inline operator float * (void) { return _v; }
+
 	friend inline ostream& operator << (ostream& output, const Vec4& vec)
         {
 	    output << vec._v[0] << " "