include cerfcpp as external (<..>) to facilitate automatic analysis

Core/Computation/RoughMultiLayerComputation.cpp

@@ -23,7 +23,7 @@
 #include "Sample/Slice/LayerInterface.h"
 #include "Sample/Slice/LayerRoughness.h"
 
-#include "cerfcpp.h"
+#include <cerfcpp.h>
 
 // Diffuse scattering from rough interfaces is modelled after
 // Phys. Rev. B, vol. 51 (4), p. 2311 (1995)