Improve logic handling events

We now throw away redundant events, just as we throw away other redundant
data coming from the dive computer. Events are considered redundant if
they are less than 61 seconds apart and identical.

This also improves the display of the remaining events in the profile as
we now show the value of the event, if it is present (for example for a
deco event we show the duration of the deepest stop).

Finally, for events that define a range (so they set the beginning flag
and assume and end flag some time later) we no loger show the triangle but
assume that some other code handles visualizing them (as happens for the
ceiling events).

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

gtk-gui.c

@@ -1231,7 +1231,7 @@ void attach_tooltip(int x, int y, int w, int h, const char *text)
 	rect->y = y;
 	rect->width = w;
 	rect->height = h;
-	tooltip_rects[tooltips].text = text;
+	tooltip_rects[tooltips].text = strdup(text);
 	tooltips++;
 }