Clean up framing compiler warnings

* Remove unused variables/dead code
* Add missing `.children = {}`
* Remove relative includes

rtgui/compressgamut.cc

@@ -24,7 +24,7 @@
 
 #include "eventmapper.h"
 
-#include "../rtengine/procparams.h"
+#include "rtengine/procparams.h"
 
 using namespace rtengine;
 using namespace rtengine::procparams;