updates from mlz repo

- asynconn: raise * from *
- asynconn: correct handling for timeout in AsynSerial
- add new py35compat
- target unit $

Change-Id: I052185ad3ebb3e3d1e3374f7ece9c7df06223951

secop/lib/py35compat.py

@@ -0,0 +1,58 @@
+#  -*- coding: utf-8 -*-
+# *****************************************************************************
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+#   Markus Zolliker <markus.zolliker@psi.ch>
+#
+# *****************************************************************************
+"""workaround for python versions older than 3.6
+
+``Object`` must be inherited for classes needing support for
+__init_subclass__ and __set_name__
+"""
+
+
+if hasattr(object, '__init_subclass__'):
+    class Object:
+        pass
+else:
+    class PEP487Metaclass(type):
+        # support for __set_name__ and __init_subclass__ for older python versions
+        # slightly modified from PEP487 doc
+        def __new__(cls, *args, **kwargs):
+            if len(args) != 3:
+                return super().__new__(cls, *args)
+            name, bases, ns = args
+            init = ns.get('__init_subclass__')
+            if callable(init):
+                ns['__init_subclass__'] = classmethod(init)
+            newtype = super().__new__(cls, name, bases, ns)
+            for k, v in newtype.__dict__.items():
+                func = getattr(v, '__set_name__', None)
+                if func is not None:
+                    func(newtype, k)
+            if bases:
+                super(newtype, newtype).__init_subclass__(**kwargs)  # pylint: disable=bad-super-call
+            return newtype
+
+        def __init__(cls, name, bases, ns, **kwargs):
+            super().__init__(name, bases, ns)
+
+    class Object(metaclass=PEP487Metaclass):
+        @classmethod
+        def __init_subclass__(cls, *args, **kwargs):
+            pass