Fix for the Create Image of Chart button issue.

This fixes issue #60. The fix dealt with changing a few ids and classes and how the different divs and elements are hidden.

The changes in the index.html file show that. The div which had the class "downloadLinks" now has an id "downloadLinksDiv". That id will be used to show the links and to hide the links. And it is only that div that is changed, the elements inside that div will not be changed.

Anyway, the only place where that div changes is in line 711 if js/chartbuilder.js.