Rename/repackage chatbox functionality

[Jameskmonger]

We could get some benefit from renaming and/or repackaging the chatbox functionality as well as adding docs to it

• Chatbox.inputType
  0 is default
  1 is "Enter amount"
  2 is "Enter name"
  3 is "Enter object name" (is this vanilla?? what is this?)

   should create an enum for this
  

• Chatbox.messagePromptRaised
  opens some input box without a heading, covering chatbox
  what is this? would be good to add docs explaining usage

• Chatbox.inputMessage
  this is the currently typed message