Add local copy dir and v0.2 fixes

This adds new config options and functionality for automating the process of managing repo files from a build/signing machine that is completely offline.

There are also a couple fixes for the v0.2 release. After this is included, I think v0.2 is ready for release!

Which reminds me, @mvdan, do you want to manage fdroidserver on pypi? I'm happy to do it or hand it over to you.