Use a normal object when setting up the author object.

[Wilfred]

Object.create(foo) produces an object that inherits properties from foo. This isn't necessarily harmful, but it can cause surprising behaviour:

> console.log(msg.message.user)
{ reply_to: 'test_room@conf.btf.hipchat.com',
  room: 'test_room' }
> typeof msg.message.user
"object"
> console.log(msg.message.user.name) // should be undefined, surely?
"Wilfred Hughes"

I think this is a worthwhile change as it makes debugging plugins easier.