Changes to behavious of FitToMarkers:
      - in order for the fit to markers to behave as suggested and be independent of the center marker changing, some reshuffling of the code occurred.
      - the center marker is no longer stored in markers, but rather stored on it's own.
      - if there is a change to one of the marker's locations, the map will pan to fit the markers.
      - Note: this does not include the center marker nor draggable markers.
      - Note: It is also base upon the assumption that if the order of the markers changes, then this is a 'change'.
             - if this feature were to be revoked there needs to be a change to the method in which the markers lat/lng are compared.
                  (This may result in potentially slightly worse performance.)
      - Rather than onMutation event handler, one that just observed 'markers' was found to be more appropriate.
                  (Otherwise the map would only change when the was a mutation on the map and it would strangely jump.)