Fix hanging issues on massive commands sending

The test When_posting_20_commands_to_server**** reproduced the issue:
no one of 20 started tasks were completed. The code been hanging on the
HttpClient.PostAsync call. So the WebAPI lib has been updated to the
latest version which means ASP.NET WebAPI is used now instead of WCF
WebAPI.

1. Removed old WebAPI stuff and updated the Microsoft.AspNet.WebApi.*
   package to the latest version. CommandsController replaced the
   CommandsService.
2. Updated JsonNetFormatter implementation and updated the code.
3. Introduced WebAPI.SelfHosted and WebHosted usage.
4. AbstractBasicAuthenticationHandler, SimpleBasicAuthenticationHandler
   has been removed as depricated. Global AuthenticationFilter is used
   now.
5. Upgraded Json.NET, OData, Rx, etc packages
6. Changed server side initialization: ZazServer helpder class been
   introduced. See the Sample project for details.