improve handling of module init methods

- complain when super call is omitted (this is a common programming
  error in Mixins)
- redesign waiting mechanism for startup

+ rename MultiEvent method 'setfunc' to 'get_trigger'

Change-Id: Ica27a75597321f2571a604a7a55448cffb1bec5e
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27369
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

secop_psi/ls370res.py

@@ -76,8 +76,8 @@ class Main(HasIodev, Drivable):
     def register_channel(self, modobj):
         self._channels[modobj.channel] = modobj
 
-    def startModule(self, started_callback):
-        started_callback()
+    def startModule(self, start_events):
+        super().startModule(start_events)
         for ch in range(1, 16):
             if ch not in self._channels:
                 self.sendRecv('INSET %d,0,0,0,0,0;INSET?%d' % (ch, ch))