Use of non global tiles

[felixcremer]

We have a first proof of concept for the tiling of a large diskarray at PyramidScheme.Jl
Would it be possible to expose these tiles, so that they could be plotted by Tyler?

I can post an example of the pyramids later.

[rafaqz]

@SimonDanisch this is the same thing we need for using Tyler as a datashader.

Tiles that don't necessarily use the standard positions or zoom levels of XYZ tiles