Sketch of VT-based context. Refs #64.
Merge branch 'dev' into vt-context
Merge branch 'dev' into vt-context
Update feature loading for geocode test.
Fix call order.
Handle multiple results from query by sorting by distance.
Clean up features from vt context.
Merge branch 'dev' into vt-context
Handle geocoder_layer param if present.
Remove zipcode from the equation.
Update index tests.
Update s3 index configs for context testing
Add context tests, esp. for legacy utfgrid.
Merge pull request #85 from mapbox/vt-context

VT context