fixed connectTo() for direct device to control system connections when using the [] operator on the device module

Include descriptions of the owning Module in the descriptions of each process variable to make them more complete.

fixed not creating some of the application varibales with wait_for_new_data despite they were specified as push inputs

Updated to use the new ReadAnyGroup instead of the old readAny function. Some tests are still hanging or failing (mostly due to shutdown issues)

Use one file per class. Also, use boost::core::demangle instead of
checking for abi::__cxa_demangle by ourselves.

We have a visitor now for generating
 - the XML
 - the Module's dot graph
 - the textual dump of the VariableNetwork
 - the dot graph of the VariableNetwork

It inherits two functions from its two base classes. Explicitly use the
one from ApplicationBase.

use a different work around for the thread_local problem: moving the code using the thread_local specifier to the cc file also solved the problem and does not require a complicated work around using a map...

necessary changes for the latest DeviceAccess update (readAsync() return type no longer a reference, and other related changes)

Changed an exception into an assert, since the function is only internally used and the exception is never thrown. Clafiried the documentation about this.

removed incorrect implementation of operator[] and operator() in ApplicationModule (and use the implementations of ModuleImpl instead)

refactored a type if-then-else monster into a for_each loop and exlcuded a pure cout function from the converage report

fixed bug that using poll-type transfers in testable mode could sometimes lead to stalled tests or assert failures.

- clarified some comments

added move-assignment operators for the accessors, which is required to use move-assignment operators of modules containing accessors

Proper implementation of move constructors and move assignment operators for all module types (including tests for the assignment operator)