Adds support for a data_url to the raster api
Added check for bad status code when trying to download data_url
Update buildout_gis_compile.cfg

Changed source download url from ftp to http.
Adds openlayers js, css and images to the visualiser (rather than relying on the openlayers site)
Zoom map to Australia's bounds.
Merge branch 'master' of github.com:BCCVL/BCCVL_Visualiser into add_combined_salt_buildout_support