packaging: require mercurial >= 4.5
Otherwise building the doc package fails with:
(third party extension evolve requires version 4.5 or newer of Mercurial; disabling)
Exception occurred:
File "/usr/lib/python2.7/dist-packages/mercurial/help.py", line 624, in help_
raise error.Abort(msg, hint=hint)
Abort: no such help topic: evolve
syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
^tests/.*\.err$
^tests/easy_run.sh$
^build/
^dist/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes
^docs/training/graphs/
^docs/training/html/
^docs/training/index.html
^docs/training/graphviz-images/
^docs/training/img/
^docs/training/output/
^docs/training/pandocfilters/