fix some remaining py3 incompatibilites

- None <= 0  is invalid in py3
- restrict BLOBType to bytes (may be changed after migration to py3)
- remove long
- use list(<dict>.items()) when dict is changed within loop
- allow initialization of properties in HasProperties without
  supercall to base class
- <dict>.values() can not be indexed
- adapted/removed various tests. additional tests might be added
  after definitive migration to py3

after this change, all the tests run with py3, also secop-server and
secop-gui were tested with an example, but other code might still contain
py3 incompatibilities

Change-Id: I881c6972aeabb8494a21a6cbc7ffeddfd4f5d4f8
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21306
Tested-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Reviewed-by: Bjoern Pedersen <bjoern.pedersen@frm2.tum.de>

test/test_properties.py

@@ -47,16 +47,15 @@ V_test_Property = [
     [(IntRange(), 0, '', False, False),
      dict(default=0, extname='', export=False, mandatory=False)],
     [(IntRange(), None, '', False, False),
-     dict(default=None, extname='', export=False, mandatory=True)], # 'normal types + no default -> mandatory
+     dict(default=0, extname='', export=False, mandatory=True)], # 'normal types + no default -> mandatory
     [(ValueType(), None, '', False, False),
      dict(default=None, extname='', export=False, mandatory=False)], # 'special type + no default -> NOT mandatory
 ]
-def test_Property():
-    for entry in V_test_Property:
-        args, check = entry
-        p = Property('', *args)
-        for k,v in check.items():
-            assert getattr(p, k) == v
+@pytest.mark.parametrize('args, check', V_test_Property)
+def test_Property(args, check):
+    p = Property('', *args)
+    for k,v in check.items():
+        assert getattr(p, k) == v
 
 def test_Property_basic():
     with pytest.raises(TypeError):