Decompress gzipped tile responses if no -ensure-gzip flag

[spwoodcock]

Fixes #37

[iandees]

The code is like this because the mbtiles spec (and all mbtiles readers that I've used) expect to see the data gzipped if the tiles are pbf. Having said that, I agree that the flag's semantics make this change correct.

[spwoodcock]

The code is like this because the mbtiles spec (and all mbtiles readers that I've used) expect to see the data gzipped if the tiles are pbf. Having said that, I agree that the flag's semantics make this change correct.

Ah yes, very good point!

Vector tiles need gzipped PBF, while raster mbtiles need non-gzipped PNG or JPEG.

Perhaps we can have conditional logic based on the mbtiles-format flag? If PBF, then keep compressed. If not, then decompress.

I'll update the code 😃