removed old style syntax

- removed secop/metaclass.py
- moved code from ModuleMeta to modules.HasAccessibles.__init_subclass__
- reworked properties:
  assignment obj.property = value now always allowed
- reworked Parameters and Command to be true descriptors
- Command must now be solely used as decorator
- renamed 'usercommand' to 'Command'
- command methods no longer start with 'do_'
- reworked mechanism to determine accessible order:
  the attribute paramOrder, if given, determines order of accessibles
+ fixed some issues makeing the IDE more happy
+ simplified code for StatusType and added a test for it

Change-Id: I8045cf38ee6f4d4862428272df0b12a7c8abaca7
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/25049
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/ah2700.py

@@ -20,7 +20,7 @@
 # *****************************************************************************
 """Andeen Hagerling capacitance bridge"""
 
-from secop.core import Readable, Parameter, Override, FloatRange, HasIodev, StringIO, Done
+from secop.core import Readable, Parameter, FloatRange, HasIodev, StringIO, Done
 
 
 class Ah2700IO(StringIO):
@@ -29,12 +29,12 @@ class Ah2700IO(StringIO):
 
 
 class Capacitance(HasIodev, Readable):
-    parameters = {
-        'value': Override('capacitance', FloatRange(unit='pF'), poll=True),
-        'freq': Parameter('frequency', FloatRange(unit='Hz'), readonly=False, default=0),
-        'voltage': Parameter('voltage', FloatRange(unit='V'), readonly=False, default=0),
-        'loss': Parameter('loss', FloatRange(unit='deg'), default=0),
-    }
+
+    value = Parameter('capacitance', FloatRange(unit='pF'), poll=True)
+    freq = Parameter('frequency', FloatRange(unit='Hz'), readonly=False, default=0)
+    voltage = Parameter('voltage', FloatRange(unit='V'), readonly=False, default=0)
+    loss = Parameter('loss', FloatRange(unit='deg'), default=0)
+
     iodevClass = Ah2700IO
 
     def parse_reply(self, reply):