add more tests and fixes for command inheritance

- fix CommandType.__repr__
- secop/modules.py: command properties are allowed to be configured:
   - section 2: remove comment and rename
   - section 3: all accessible properties should be checked
- command description should be inherited also when taken from docstring
- move test for command inheritance to test_modules.py
- added tests to check for valid properties of commands

Change-Id: I5fd04e03be1faec5e54fed9735620bc5dc0f89c0

test/test_params.py

@@ -98,6 +98,12 @@ def test_Override():
     Mod.p1.default = False
     assert repr(Mod.p1) == repr(Base.p1)
 
+    for cls in locals().values():
+        if hasattr(cls, 'accessibles'):
+            for p in cls.accessibles.values():
+                assert isinstance(p.ownProperties, dict)
+                assert p.copy().ownProperties == {}
+
 
 def test_Export():
     class Mod(HasAccessibles):