Introducting soft-proofing and Black Point Compensation, simplify the

CMM at the end of the pipeline + sparse code refactoring
A new BPC checkbutton has been created in 'Preferences/Color Management'
and in the ICM tool. Better hanbling of widget sensitivity of the output
profile / gamma part of the ICM tool.

rtengine/procparams.h

@@ -967,6 +967,7 @@ public:
     Glib::ustring working;
     Glib::ustring output;
     RenderingIntent outputIntent;
+    bool outputBPC;
     static const Glib::ustring NoICMString;
 
     Glib::ustring gamma;