Added tags to taglib to check for connected and disconnected state

I've added in two tags, one to check if connected, and one to check if disconnected. I'm not 100% if I've done the check correctly, if I should just be checking for the token in the session to be null, but it should be easy to adjust if I haven't done it the right way. Let me know if something needs to be adjusted or not.

Basically, this just allows an easy way of in the gsp of showing certain content when connected and when disconnected.