patch: monotone source for mercurial convert extension

[Mikkel Fahnøe Jørgensen]

> Would you provide a test for the monotone converter ?
>
>  There are many examples in tests/test-convert*. Most of them create a repository exercizing binary files, branches, tags or other supported features, convert it once, update the source repository again with tricky revisions and test the incremental conversion again. Doing this requires a good knowledge of the source repository format as well as a good overview of what is supported by the conversion code, which you have.
>
>  We can certainly help you writing it if you have any problems with the test suite.

I will have a look at it when I get through some other work piling up,
then I can see if it is something that I can add on my own.

Regards,
Mikkel