tighten up list view when there are not any images
clean up description visibility call

removed unnecessary param from Map constructor
add Zoom Out link to popups and customize maxZoom

maxZoom is in configuration, but Zoom out link button is added to all
fix legend visibility, add new way of centering points

add a configuration to leave default centering behavior when list points
are clicked, or have each re-center according to zoom level in the
spreadsheet.