specifying input format for buffer point
buffer point now uses point geojson to create a buffer
Merge branch 'master' into dev

* master:
  only deflate if request header asks for it - specifically for dynamically created Vector Tiles. Causes 'Unimplemented type' errors in client libraries trying to parse the result.
If no deflate header is requested, then pass on without deflating.
Updated version of mbtiles module.  Newest version detects compression type of .pbfs stored in mbtiles, so we know which content-encoding header to send back to the client.
(this is because Mapbox Studio now gzips .pbfs rather than deflate).  We now serve both.
Also, gzipping dynamically-created pbfs from PG endpoints.
Make sure the compression type specified by TileType matches the requester's compression type.
If no match, zlib.unzip, otherwise set the correct outgoing content-type.
This is a fix for headless browser requests (like in phantomjs).