User typing additions

[TriggerAu]

Adjusted the routing on the Typing class to fix the SendTyping call and added a new class to receive the "user_typing" messages. For the second one I renamed the empty UserTyping method but maintained the scope etc

Hope the structure is good and if code comments are helpful just let me know

Relates/Fixes bug #203 that I logged when finding it

[Inumedia]

Hey TriggerAu,

I'm not sure I understand the point of this PR other than to separate the receiving of this message from the sending of this message?

I don't mind the OnTyping event being added, but I am slightly concerned about the splitting of the receive/send of the event.

[TriggerAu]

Thanks for lookingIll try and clarify how I got there.

The problem I struck was that on calling SendTyping the packet sent to the slackApi contained the message "user_typing" as the type to slack. It appeared to me that this was due to the WebSocketMessages class UserTyping.cs having two SlackSocketRouting attributes with different types "typing" and "user_typing". The only other class that was similar was newMessage.cs but the type is the same with one having a subtype.

Thus I split the sending and receiving type's to different classes. Hope that clarifies it