pmtiles-serve serves tiles with TMS scheme

[typebrook]

Problem: Now pmtiles-serve directly uses y value in sqlite table tiles from MBTiles, which is TMS scheme.

In fact, MBTiles always follow TMS scheme. So if we want to serve tiles with XYZ scheme, the y value should be

# y is the value in MBTiles
2^z - 1 - y 

[bdon]

@typebrook can you try with version 0.0.5?

[typebrook]

@bdon Looks good on latest version! Well done!