Keys no longer display Toast for color, minor internal refactoring in preparation for using iterator to verify user input.
Changed all internal Button references to View; View has setPressed() method and all needed behaviors.
More internal refactoring, plus added a "start game" button that plays the pattern and awaits response. The response from the system about whether or not the pattern is OK isn't working. It might be a problem with getting the Context from the view to display a Toast. Perhaps I should cast it to Activity.