#283 Custom tile processing for OSMAND maps

[Vasco]

I have a (local) tilesource with 1024x1024 tiles. On my phone using OSMAND, this tilesize loads only slowly. I like to adjust the map tiles to 256x256 px. Currently, this is not supported by Mobac (as listed in the readme):

As atlases for OSMAND do not support all features provided by Mobile Atlas Creator the following settings are ignored when creating atlases for OSMAND:

Change height or width of the map tiles
Name of all layers and maps
Structure of the atlas (which maps belongs to which layer)

Feauture request: enable tiles reslicing for OSMAND maps.