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.

echo % initialize remote repo with branches
hg init remote
cd remote
echo a > a
hg ci -Ama
hg branch br
hg ci -Amb
echo c > c
hg ci -Amc
hg log

cd ..
echo % try cloning -r branch
hg clone -rbr remote local1
hg -R local1 parents

echo % try cloning -rother clone#branch
hg clone -r0 remote#br local2
hg -R local2 parents

echo % try cloning -r1 clone#branch
hg clone -r1 remote#br local3
hg -R local3 parents