Changes

Summary

1. tuned (graph.all_succs already contains origin);
2. support for AFP versions; added AFP tests: non-slow, two partitions;
3. clarified afp_pull_date: both repository versions are relevant;
4. clarified stored build_args;
5. partition AFP sessions according to structure, which happens to cut it roughly into equal parts;
6. support for AFP in build_history and remote_build_history;
7. tuned whitespace;
8. support for AFP versions;
9. tuned signature;
10. tuned signature;
11. support for AFP versions;
12. tuned;