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>

test/test_datatypes.py

@@ -25,7 +25,7 @@
 # no fixtures needed
 import pytest
 
-from secop.datatypes import ArrayOf, BLOBType, BoolType, \
+from secop.datatypes import ArrayOf, BLOBType, BoolType, Enum, StatusType, \
     DataType, EnumType, FloatRange, IntRange, ProgrammingError, ConfigError, \
     ScaledInteger, StringType, TextType, StructOf, TupleOf, get_datatype, CommandType
 
@@ -359,6 +359,7 @@ def test_BoolType():
         # pylint: disable=unexpected-keyword-arg
         BoolType(unit='K')
 
+
 def test_ArrayOf():
     # test constructor catching illegal arguments
     with pytest.raises(ValueError):
@@ -478,6 +479,14 @@ def test_Command():
         'result':{'type': 'int', 'min':-3, 'max':3}}
 
 
+def test_StatusType():
+    status_codes = Enum('Status', IDLE=100, WARN=200, BUSY=300, ERROR=400)
+    dt = StatusType(status_codes)
+    assert dt.IDLE == status_codes.IDLE
+    assert dt.ERROR == status_codes.ERROR
+    assert dt._enum == status_codes
+
+
 def test_get_datatype():
     with pytest.raises(ValueError):
         get_datatype(1)