add prechangegroup and pretxnchangegroup hooks.
prechangegroup lets you stop push, pull or unbundle before it begins.
pretxnchangegroup lets you inspect changegroup before transaction is
committed, and roll back if you not like it.
include hg
recursive-include mercurial *.py
include hgweb.cgi hgwebdir.cgi
include hgeditor rewrite-log
include tests/README tests/run-tests tests/test-*[a-z0-9] tests/*.out
prune tests/*.err
include *.txt
include templates/map templates/map-*[a-z0-9]
include templates/*.tmpl
include doc/README doc/Makefile doc/*.txt doc/*.html doc/*.[0-9]
recursive-include contrib *
include README
include CONTRIBUTORS
include COPYING
include Makefile
include MANIFEST.in