convert/gnuarch: parse continuation-of revisions in gnuarch source In GNU Arch, continuation-of was often used for: - tagging revisions - continue working on a project in a new archive, because arch was scaling poorly in revision numbers (cat-logs were slow to be parsed and scanned through) - very similar to the previous point, fork his own branch of a project. Parsing this header information will allow to 'follow' new history because it often hints at older/forked/personal revision trees. This patch however just implements the parsing of the continuation-of header. A followup patch will implement the proper use of this new information.

changeset:   0:9426b370c206
tag:         tip
user:        My Name <myname@example.com>
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     commit-1

changeset:   1:4997f15a1b24
tag:         tip
user:        foo@bar.com
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     commit-1

changeset:   2:72b8012b424e
tag:         tip
user:        foobar <foo@bar.com>
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     commit-1

changeset:   3:35ff3067bedd
tag:         tip
user:        foo@bar.com
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     commit-1

abort: Please specify a username.
No username found, using user@host instead