WhereOnEarth - Logic to advance to end screen

- Renaming method showEnding to createEndView
- Updating showNextQuestion to now advance to the endView screen when
the user has been through all the questions. (note we’re making use of
the same replaceView method that does the fade animation on the quiz
screen).
WhereOnEarth - slight layout change on answers

Changing some of the x, y parameter values so the layout looks good
with the 4 answer buttons.