logout implemented

[kevinleung23]

• AccountController Logff HttpPost implemented
• Added
  to /home/index.cshtml
• Link submit .js refactored to wwwwroot/Scripts/Home.js
• Fixed Logoff UI arrow in index.cshtml
• Changed redirect to ~/account/forbidden/ to ~/account/login/

TODO: #254

[jcocchi]

Logging out itself seems to work, you can log out any user and log in another user after and messaging in rooms, creating rooms all work fine. But if you log out a user and then try to log that user back in you get a self referencing loop exception on the Clients.Caller.userNameChanged(user) line on chat.cs 92

• Removing this line will fix the user logging out twice error, but creates other errors documented in issue #129
• Full self referencing loop error message: An exception of type 'Newtonsoft.Json.JsonSerializationException' occurred in Newtonsoft.Json.dll but was not handled in user code. Additional information: Self referencing loop detected for property 'UserKeyNavigation' with type 'JabbR_Core.Data.Models.ChatUser'. Path 'A[0].ConnectedClients[0]'.

[kevinleung23]

PR on hold until we figure out self referencing loop error. #129