hidden: Add a hiddenrevs attributes to changelog.
This attributes hold the set of all revisions that should be ommited by command
and tools displaying changesets.
This set is given as a hit. Command and tools are responsible to check it in
order to filter they outpur.
Code adding revisions to the set are responsible to the consistency of it's
data.
To run the tests, do:
cd tests/
python run-tests.py
See http://mercurial.selenic.com/wiki/WritingTests for
more information on writing tests.