[PATCH 0 of 6] More convert extension love

[Edouard Gomez]

After the merge of the convert extension, there is still a
few fixes and improvements that would be cool pushing to
crew.

Bugfixes:
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summary:     Add hgext.convert to setup.py
summary:     Fix hgext/convert/__init__.py rights

Enhancements:
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summary:     Save a few opens on the map file
summary:     Add support for username mapping

Last time they were not understood, maybe they will:
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summary:     Add some more smart when initializing destination repository
summary:     Initialize source repository after destination one