stablerange: introduce a basic-mergepoint method This method use the new 'mergepoint' based stable sorting. It is expected to be eventually better than branch point to stable range: more stable, easier to cache, etc. Having a basic implementation will allow use to validate more advanced implementation.

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