Tiles for dev3map

Tiles are stored in the format <tileset name>/z<zoom>/<x>,<z>.png where x and z are the coordinates of that region, and zoom is 0 for one pixel per block and decreases by 1 every time the viewport width is doubled.

All tiles are 256x256 pixels in size, so at zoom level 0 each tile contains the data from one Minecraft .mca region file.