add support for OpenScienceMap formatted binary tiles to VecTiles provider
OSciMap-formatting code mostly copied from: https://github.com/opensciencemap/TileStache/tree/master/TileStache/OSciMap4
todo: cleanup, add MultiResponse ('all') support
adding support for opensciencemap (vtm) multiprovider. moving db/feature stuff into get_features
adding pbf_test
EmptyResponse instance has no attribute 'coord'
Moving lines that write json stream to a file into its own function
adding OsciMap4 to the packages array
moving get_tiles into server.py and using it for both formats.
unknownLayerMessage: A message that notifies that the given layer is unknown and lists out the known layers.
printing and logging all exceptions in addition to core.knownunknowns
descriptive error messages
Merge branch 'better-error-responses' into integration-1
Merge branch 'add-opensciencemap-vectiles' into integration-1

Conflicts:
	TileStache/Goodies/VecTiles/server.py