improve frappy.errors

- include all secop errors from spec
- add doc strings
- make conversion to and from error report nicer
- move all error classes to frappy.errors
- rename errors clashing with built-in errors

Change-Id: I4d882173b020cd4baf862c5891375b691e67e24a
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/30721
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

frappy/io.py

@@ -31,7 +31,8 @@ import threading
 from frappy.lib.asynconn import AsynConn, ConnectionClosed
 from frappy.datatypes import ArrayOf, BLOBType, BoolType, FloatRange, IntRange, \
     StringType, TupleOf, ValueType
-from frappy.errors import CommunicationFailedError, ConfigError, ProgrammingError
+from frappy.errors import CommunicationFailedError, ConfigError, ProgrammingError, \
+    SilentCommunicationFailedError as SilentError
 from frappy.modules import Attached, Command, \
     Communicator, Module, Parameter, Property
 from frappy.lib import generalConfig
@@ -41,10 +42,6 @@ generalConfig.set_default('legacy_hasiodev', False)
 HEX_CODE = re.compile(r'[0-9a-fA-F][0-9a-fA-F]$')
 
 
-class SilentError(CommunicationFailedError):
-    silent = True
-
-
 class HasIO(Module):
     """Mixin for modules using a communicator"""
     io = Attached(mandatory=False)  # either io or uri must be given