merge 3.0-panexp (pan experiments) branch, revisions 8534-8585 into 3.0, thus ending 3.0-panexp. THIS COMMIT WILL BREAK ALL EXISTING 3.0 SESSIONS IN SOME WAY (possibly not fatally).

git-svn-id: svn://localhost/ardour2/branches/3.0@8586 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/evoral/src/ControlList.cpp

@@ -394,6 +394,10 @@ ControlList::add (double when, double value)
            control surface (GUI, MIDI, OSC etc) 
         */
 
+        if (!clamp_value (when, value)) {
+                return;
+        }
+
 	{
 		Glib::Mutex::Lock lm (_lock);
 		ControlEvent cp (when, 0.0f);