Introducing dynamic settings

This branch introduces the app.config file and the settings class. The settings class resides at namespace Rhenus.Spring.Configuration and is implemented as a singleton. It is able to read and write to the app.config file, but only to the Rhenus.Service section group. The app.config file is renamed to the name of the outfile during the build and is set to some default values. 

At the moment only an example is filled in to get this thing working, but value defaults and application settings will be added along the way.