This records the branches starting at individual CVS file revisions,
using the symbolic names map rather than just the branches
information. This information is used to generate Mercurial
changesets. Despite the changes, the CVS conversion still suffers
heavily from cvsps' deficiencies in generating a correct
representation of the CVS repository history.
Source and destination constructors should be fast so configurations issues are
hit quickly, including authentication and filemap/authormap/splicemap issues.
Delaying might be a problem if the remove side disconnects idle connections
while the log is being read. It did not happen when converting openafs
repository, where log retrieval took at least 10mn.