REACH-93 Create new Home workspace in nwk

Add a possibility into Flood to clear Home workspace with checking presence of unsaved changes 
[Here's a link to this task](http://adsk-oss.myjetbrains.com/youtrack/issue/REACH-93)

Do we always want to ensure a valid ```Guid``` value?

 - If so, then we can use ```string.IsNullOrEmpty``` and ```Guid.TryParse``` to ensure we get the well-formatted ```Guid``` string, then throw an ```ArgumentException``` if it's invalid.
 - If not, then we can use the same methods for validation, and set to ```string.Empty``` instead of throwing an exception.
 
The current check against `null` seem to be insufficient.