Mirror lists

[frauzufall]

Imagine there is a base list (e.g. sites.yml) and a directory called mirrors where people could add mirror servers. One mirror file would contain something like this:

• a list containing IDs of update sites linked to the URLs of their servers
• if they mirrored sites.imagej.net, it would contain the replacement for this path as well
• the location of the mirror server

The updater could then provide the user with a choice to pick from depending on their location.