Modified the GEO label SVG output (SVG.php file):
  * Removed "<?xml version="1.0"..." and "<!DOCTYPE svg..." from the SVG header because these declarations were causing errors when trying to incert the SVG into an HTML page.
  * Modified GEO label SVG's ID from id="Layer_1" to id="geolabel_svg".
Added a new demo.html page for demonstrating the GEO label API functionality.
  * The demo.html page will use actual API end points (not the /geolabel/demo POST end point).
  * jQuery and Ajax are used to send GET requests to obtain GEO label representation.
  * The resulting GEO label is displayed on same page as the form.
  * The geolabel.html will temporarily remain until no longer used in the tutorial.