Refactoring and Cleanup
Implemented US#14

Changed the type of a DiagnoseOutputEntry to an enum
Fixed bug in the CsvReceiver
Implemented error handling when initializing a receiver
Implemented US#15

Added new ReactiveCommand for handling the closing of a session.
Merge pull request #11 from GraphalyzerPro/US#14-US#15

Implemented US#14 and US#15