makeButton function
makeButton function

Use makeButton instead of having the
  next and previous buttons in the dom.

if the buttons are removed,
  this.prevButton/this.nextButton store the respective elements

The buttons are always inserted at/removed from index 0
This is to ensure that the correct button is being removed/added
  - on condition that the other buttons are being
      pushed/popped from the controls.

googlearchive/google-map-storyboard,jackass0528/google-map-storyboard,googlearchive/google-map-storyboard,jackass0528/google-map-storyboard