Introduced new osg::discardDeletedOpenGLObjects() methods, and usage of it in

GrpahicsContext::close() to handle cases where deletingOpenGLObjects is no possible,
such as when GraphicsWindowEmbedded is used.

src/osgWrappers/osg/Shader.cpp

@@ -153,6 +153,10 @@ BEGIN_OBJECT_REFLECTOR(osg::Shader)
 	                __void__flushDeletedGlShaders__unsigned_int__double__double_R1_S,
 	                "flush all the cached glShaders which need to be deleted in the OpenGL context related to contextID. ",
 	                "");
+	I_StaticMethod1(void, discardDeletedGlShaders, IN, unsigned int, contextID,
+	                __void__discardDeletedGlShaders__unsigned_int_S,
+	                "discard all the cached glShaders which need to be deleted in the OpenGL context related to contextID. ",
+	                "Note, unlike flush no OpenGL calls are made, instead the handles are all removed. this call is useful for when an OpenGL context has been destroyed. ");
 	I_StaticMethod1(osg::Shader::Type, getTypeId, IN, const std::string &, tname,
 	                __Shader_Type__getTypeId__C5_std_string_R1_S,
 	                "",