This is to support when running under Boost::Test which will swallow the
message otherwise and print the confusing ~AppBase() message of not
being properly shut down

This can be overridden by a newly introduced boolean argument. Including the return channel was causing problems e.g. when propagating the DataValidity flag.

- Exception handling decorator does not allow to leave testable mode before
  devices are up
- Test facility makes sure that testable mode counter is zero at the end of startApplication()

- first part of #102
- Existing tests passing
- New tests not activated yet

wip #47: register accessor for write after open in DeviceModule if write cannot be performed in initialisation phase

change declaration of 'decrementDataFaultCounter' in 'EntityOwner' to take a bool parameter and adjust rest of the code to it
implement 'decrementDataFaultCounter' in 'ApplicationModule' according to ticket #95 -> rewrite all outputs when 'faultCounter' goes from 1 to 0

		writeAfterOpen writes constants to devices
		remove writeAfterOpen in recovery loop
			that should be in writeRecoveryOpen
		extend testProcessVariableRecovery for constants

remove commented part of ExceptionHandlingDecorator - 'void doPreRead() override' and its implementation

removed doPreRead() / doPreWrite() , doPostRead() / doPostWrite() from ExceptionHandlingDecorator - tests are now failing

  - Handle illegal writes to read-only accessors in doPreWrite().
    Otherwise, attempting to write to the recovery accessor would result
    in a nullpointer access.
  - Related test case.

  - Cleaned up comments
  - Place using-declaration of buffer_2D to class definition so the base
    class name can be omitted in the implementation