contrib: add Chris Mason's stand-alone diff tool
This uses Mercurial's diff algorithm to generate unidiffs like the traditional diff tool.
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