Mercurial/HG convert plugin with a few new features

I wanted to have an option to convert hg repo with file mapping without being history stripped.

• hg convert --config convert.prefixempty=true --config convert.hg.allowempty=true --sourcesort --filemap ${FILEMAP} ${SRC} ${DEST}

• --config convert.hg.allowempty=true: Can save history under filemap enabled
• --config convert.hg.allowempty=true: Can produce empty commits if needed
• --config convert.prefixempty=true: Can prefix empty commits that were not skipped

• python 2.7
• mercurial 2.7.1-2ppa1~raring1 (http://ppa.launchpad.net/tortoisehg-ppa/releases/ubuntu)