Greatly improved selection of polygons on map

Polygons are now primarily selected by border.  The highlight effect is
still present from hover and selection, but now should not interfere with
selecting other polygon features.
Only do intersection calculation if last layer is polygon
Allow selection of provider on asset map via URL
Adds maximum bounds to bbox/point geometries
Merge pull request #146 from benjwadams/improved_polygon_selection

Greatly improved selection of polygons on map
Merge pull request #147 from benjwadams/asset_map_select_provider_from_url

Allow selection of provider on asset map via URL
Merge pull request #148 from benjwadams/filter_bbox_maxbounds

Adds maximum bounds to bbox/point geometries