Ogr view model

Added an ogrItemViewModel that forwards files to our ogr2ogr service for conversion.
On drag and drop the file is uploaded to the server on a url it is loaded by the server.
Made this the default fall through for formats we don't have explicit handlers for.
Put 1MB size constraints on server and client side
Added airports.zip (shape file) to our init_test.json list

Right, that's kind of my point.  It should be named as a "thing that supports multiple formats by sending them off to a convert service that hopefully sends back some GeoJSON".  The OGRness of it is entirely unimportant and subject to change.  But if you really love the name I'll drop it. :)