Dive site handling: correctly handle the different scenarios

- do not create dive sites unless the user has accepted the changes
- all modification are tracked in the displayed_dive_site
- when the user accepts the changes, the real dive site list (and the
  selected dives) are updated according to what is in the
  displayed_dive_site

This adds quite verbose debugging messages and disables a section of code
that has a special case for data created by the Subsurface web service.
This code needs some re-thinking and should eventually go away.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/maintab.h

@@ -123,6 +123,7 @@ private:
 	bool acceptingEdit;
 	LocationManagementEditHelper *locationManagementEditHelper;
 	void updateDisplayedDiveSite();
+	void updateDiveSite(int divenr);
 };
 
 #endif // MAINTAB_H