Connecting a device only works if the PVs are readonly! So one has to
use the logical name mapping backend. This also allows to select only a
subset of the device PV to be added to the history module.

I observed that, after reading the message sometimes the log level was
wrong. Most likely because it was updated after the message was read.
Now the log level is bound to the message. This also reduces the number
ctk variables.

Fix missing object name in the example.

- worked around gcc bug buy adding a useless default constructor
- removed dangerous convenience referene which would be broken by copy constructor and assignment operator

- removed sleep
- put reading to end of loop (process initial value before blocking)

It is suffiecient to have the message being push type.
readAny of the ReadAnyGroup will update poll type variable
automatical once there was an update of the push type message.

Some custom tags from private servers have been removed.
Added "CS" tag, which allows to use findTag on the Logging module
and connect it directly to the control system.

the swicth because order is not important for these.

ModuleList serves as a container for VariableGroups. The VariableGroups
mirror xml modules in the config file.