convert: add tagmap option Tests have been updated.

convert: add tagmap logic Previously, there was no way to rewrite tags on the fly while converting. Now, we add similar logic to branchmap to provide a way to map old tags to new tags. Currently, this is not enabled since there is not yet a command-line option.

convert: avoid updating tags when there is nothing new Previously, when converting from a mercurial repo there would be an extraneous commit at the end of the convert process that would rewrite tags. Now, we check if there are any new tags before doing this rewriting.

convert: compare tags from all heads instead of just one Previously, the hg sink for puttags would just use one head for getting the old tags which would sometimes lead to tags disappearing. Now, we iterate over all heads and merge the results.

convert: add closemap option Tests have been updated.

convert: add parseclosemap method This is a copy of the parsesplicemap method and will serve as a way to specify which changesets to close while converting.

convert: add mapname parameter to checkrevformat Upcoming patches will add new map files so we change the calling sequence of checkrevformat so that error messages will let the user know which file has the wrong rev format.