In create_config_input, when creating multisite_config.xml, make lat
and lng of site element into attributes instead of making them child
elements (c.f. gh-18).

Added new 'get_svg' method for changes related to gh-7.
Added route for the get_svg action of the workflows controller (c.f. gh-7).
Changed the calculate button's click function so that it inserts the
contents of /tmp/out/output.svg into the highcharts_container element
if that file exists and only falls back out the highcharts-generated
svg images if it does not exist.  This supports changes related to
gh-7.