new global gDirs for default directories and filters; rm warnings from file loaders

standardize file save dialogs

disentangle ProjectManager from new src pair Dirs

rm all handling of warnings; just throw a runtime_error if something fails. This saves us lots of compilcations.

GUI/Model/Device/DatafileItem.cpp

@@ -22,7 +22,6 @@
 #include "GUI/Model/Data/Data2DItem.h"
 #include "GUI/Support/Util/Path.h"
 #include "GUI/Support/XML/Backup.h"
-#include "GUI/Support/XML/DeserializationException.h"
 #include "GUI/Support/XML/UtilXML.h"
 
 namespace {