Remove duplicate entry and non-contributor persons from AUTHORS file
(remove entries occasionally leaked from GCC and Mono downstreams;
revert part of commits e1dc74a7, b23e1c8a, 8747eb89)
ChangeLog: Add information about ancient release dates
Update Xerox FTP host name in overview.html

* doc/overview.html: Update FTP host name (ftp.parc.xerox.com).
Fix typo in person name in gc_cpp.h comment

* include/gc_cpp.h: Fix typo in surname (John Ellis) in comment.
Update AUTHORS file (specify email for some more contributors)
Restore contribution information for ancient releases in ChangeLog
(revert part of commit ba8ef9e)
Update AUTHORS file (add more persons mentioned in ChangeLog)