Added stub implementation for returning TileJSON from the avecado test/dev server.
Strip query parameters from string.

Eventually we might want to parse these. Or use a better / more
appropriate embedded HTTP server than this simple one.
Implemented simple TileJSON.

Uses the layers in the loaded map to generate some simple TileJSON
without the useful human-readable stuff like field descriptions or
other comments. The top-level stuff can be added / overridden by
adding `<Parameter>`s on the `<Map>` element.
Merge pull request #44 from MapQuest/serve_tilejson

Serve TileJSON