added basic integration of lensfun

so far only distortion correction, and no GUI yet

rtengine/procparams.h

@@ -831,6 +831,11 @@ class LensProfParams
 public:
     Glib::ustring lcpFile;
     bool useDist, useVign, useCA;
+    bool useLensfun;
+    bool lfAutoMatch;
+    Glib::ustring lfCameraMake;
+    Glib::ustring lfCameraModel;
+    Glib::ustring lfLens;
 
     LensProfParams()
     {
@@ -839,6 +844,7 @@ public:
     void setDefaults();
 };
 
+
 /**
   * Parameters of the perspective correction
   */