Tile matrix assumed to start at a certain point

[FrankyBoy]

Hi!

As far as I can tell, the library assumes that the world starts at <TopLeftCorner>-20037508.342789244 20037508.342789244</TopLeftCorner>. This is not guaranteed and in fact in my use case (local overlays over a base map) it is not true (eg. <TopLeftCorner>1730654.0 6154088.0</TopLeftCorner>). This results in the tiles rows/cols being miscalculated, which in turn means that the map cannot be rendered. Please check if this issue can somehow be fixed.

Cheers :)