Improve Modules Interface

Now the modules are created using a factory instead of static allocated.
  The same module can be applied to different sequences.
  Pain in the ass memory free

modules/FrameDifference.h

@@ -34,6 +34,8 @@ namespace plaYUVer
 
 class FrameDifference: public PlaYUVerModuleIf
 {
+  REGISTER_CLASS_FACTORY( FrameDifference )
+
 private:
   PlaYUVerFrame* m_pcFrameDifference;