Support OSM PBFs with coordinates using non-default granularity

[robhawkes]

osmosis allows you to export coordinates using precision / granularity different to the default OSM precision. This results in a smaller export, though the downside is that coordinates can lose their precision slightly – it's worth it for many use cases.

tilemaker has hard-coded precision values that assume coordinates are all in the default OSM precision. This means that position calculations in the resulting tiles are massively incorrect when using a non-default coordinate precision.

It would be great if coordinate precision could be provided as an argument or configuration value, or even read from the PBF (if it gets stored?).