* Map and Calendar pages (front-facing side) now support on_by_default setting

* setup.php updated for new on_by_default field when creating EventDataSource and PlaceDataSource tables

* PlaceDataSource_ArcGISREST now supports Polygon data sources, even does a reasonable job of finding centroids

* Added some files intended for the last commit, e.g. event_source_delete.phtml

* Other trivial whitespace & comment fixes