Marble/TileDownload

Perhaps create an (abstract) interface / abstract class TileProvider? Not sure, if there is an use case.

Perhaps separation between http download and tile providing since http download is needed for wikipedia (and perhaps other stuff) integration also.

What about redirects? in general it seems to be a good idea to support them, but do we also need the ability to forbid redirects of inform the user?

The TileLoader should be able to handle not only files, but also QByteArrays or whatever is delivered by the network plugin interface.

to be done