implement speech methods

[devpaul]

• say(message: string, duration?: number);
  • shows a speech bubble with the provided string
  • automatically calls silence() after duration
• sayChoices(... choices: string);
  • gives a list of choices for the user to select from
  • dispatches a choice event with the choice offset when a choice is selected
• sayQuestion(message: string, ... responses: string);
  • shows a speech bubble with text and a list of single word responses
  • dispatches a choice event with the string response
• silence()
  • closes any open dialog
  • dispatches a silence event when called

[devpaul]

Instead of methods, these should be available as separate web components