Dynamo server mode

1) Enable DynamoSandbox.exe to run in server mode
 - Use command-line switch for this (e.g. DynamoSandbox.exe /server)
 - Create a WebSocket with HttpListener for incoming connection requests

2) Establish connection to Dynamo Server through WebSocket

3) Enhance Dynamo Server to instantiate RecordableCommand objects
 - Upon receiving command requests through WebSocket, the server turns them into instances of RecordableCommand derived objects.
 - These command instances are sent to DynamoViewModel.ExecuteCommand method
 - As a result of executing these commands, a side effect is visible on server (e.g. a node is created in response to CreateNodeCommand)