Saving workspace functionality

Saving workspace functionality:
- the Dynamo receives a message about saving, saves all workspaces as files and sends them back to the Flood.

Part of changes that had to be uploaded with "Changing the way of geometry transmission" but wasn't:
- receiving a geometry message, process it and send back the geometry data

Enhancements of the code (there is not a lot of them, so I add them into this PR):
- checking for not null, correct guid, removing old code, etc
Hi @marimano, your in-line notes here on GitHub are great! Although they help me understand your code better here, you should really be adding these as comments in the code. That will be very helpful in the future if somebody looks at these codes. Could you please add the comments in the code and remove these line notes on GitHub? Thanks :)