Remove the majority of the Gtk related code

- rip all Gtk code from qt-gui.cpp
- don't compile Gtk specific files
- don't link against Gtk libraries
- don't compile modules we don't use at all (yet)
- use #if USE_GTK_UI on the remaining files to disable Gtk related parts
- disable the non-functional Cochran support while I'm at it

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

info-gtk.c

@@ -736,6 +736,14 @@ int edit_multi_dive_info(struct dive *single_dive)
 	return success;
 }
 
+int edit_dive_info(struct dive *dive, gboolean newdive)
+{
+	if (!dive || (!newdive && !amount_selected))
+		return 0;
+
+	return edit_multi_dive_info(dive);
+}
+
 static GtkWidget *frame_box(GtkWidget *vbox, const char *fmt, ...)
 {
 	va_list ap;