[Xastir-dev] New feature - Parallel background downloads

[Mike Nix]

Hi All,

I've written a Download Manager for Xastir that allows OSM tiles to be
downloaded in parallel in a separate thread.
It can also be used for any file download, so I'm sure it will
eventually be useful elsewhere.

This provides a big improvement to the map zoom/pan experience,
especially on high-latency internet connections.

Available for testing as branch DLM from
https://github.com/ChocolateFrogsNuts/Xastir

Also includes a commit with some patches for newer versions of ImageMagick.

Enjoy,
Mike