improve poller error handling

- repeated errors on poller are only once logged (per poll
  function / read_* method)
- during exception handling, silent=True on a SECoP error indicates
  that the error is already logged
+ fix the name of HardwareError
+ add test for consistency of SECoPErrors
+ catch socket.timeout in AsynTcp

Change-Id: I9df6c775cc19553b22a4d6e39591092adf7ff9a1
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/28139
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

test/test_errors.py

@@ -0,0 +1,30 @@
+#  -*- 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>
+#
+# *****************************************************************************
+"""test data types."""
+
+import secop.errors
+
+
+def test_errors():
+    """check consistence of secop.errors.EXCEPTIONS"""
+    for e in secop.errors.EXCEPTIONS.values():
+        assert secop.errors.EXCEPTIONS[e().name] == e