rewriteutil: create a rewriteutil module to host utility function The ultimate goal of this module is to gather basic building block for rewriting changesets. This is aimed at moving into core and being use by the core extension.

syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
\.err$
^tests/easy_run.sh$
^build/
^dist/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes