Merge following changes in the English version.

1.112 -> 1.113 authors.ent
1.27 -> 1.28 advanced-networking/chapter.sgml
1.20 -> 1.21 basics/chapter.sgml
1.26 -> 1.27 bibliography/chapter.sgml
1.76 -> 1.79 mirrors/chapter.sgml
1.49 -> 1.50 staff/chapter.sgml