[client] redesign of the renderer archiceture for mt support

This is the first of two commits that completely turn the rendering code
on it's head. This change set decouples the guest's capture rate from
the host's render rate for both cursor and frame updates. This helps
prevent the host application from stalling when waiting for frame draws
when all it want's to do is send cursor updates.

* Breaks OpenGL-Basic for now

client/lg-renderers.h

@@ -21,12 +21,12 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 #include "lg-renderer.h"
 
 extern const LG_Renderer LGR_OpenGL;
-extern const LG_Renderer LGR_OpenGLBasic;
+//extern const LG_Renderer LGR_OpenGLBasic;
 
 const LG_Renderer * LG_Renderers[] =
 {
   &LGR_OpenGL,
-  &LGR_OpenGLBasic,
+//  &LGR_OpenGLBasic,
   NULL // end of array sentinal
 };