Changes

Changes from Mercurial (hg http://isabelle.in.tum.de/repos/isabelle/ default)

Summary

1. clarified signature;
2. proper treatment of empty extra lines (amending 98a440cfbb2b);
3. clarified signature: explicitly typed interfaces;
4. provide maintainers as seen in AFP/admin; suppress empty properties;
5. tuned;
6. tuned signature;
7. read AFP metadata for entries;