Csv improvements

A range of csv improvements

* the init file can now set the style for layers for any layer.  examples in init_test.json
* the style is included when sharing so visuals show up the same elsewhere when possible (non d+d)
* getFeatureInfo is subclassed in the region mapping layer to allow injecting row data into the popup dialog
* The generated legend shows up for csv's and the visuals have been improved.
* the image for csv billboards is now settable and the default is now a more standard circle