mergestate.commit: factor out making the list of records Will aid in testing.

mergestate: move _read() call to read constructor With this patch, mergestate.clean() will no longer abort when it encounters an unsupported merge type. However we hold off on testing it until backwards compatibility is in place.

debugmergestate: explain why we create mergestate objects directly We would normally use the read() constructor, but in this case it's fine because - we implement our own reading layer, so the extra parsing done by read() is unnecessary - read() can raise an exception for unsupported merge state records, but here we'd like to handle that separately - debugmergestate needs to be privy to mergestate internals anyway

debugdirstate: convert keyword parameters to **opts Removes the named arguments and replaces them by accessing opts. This will be used in the next patch in the series because we'll be adding more flags to debugdirstate

convert: changed test's progress output format to ignore estimate On my machine, whenever I run all test with a high -j value, test-convert-git.t would consistently fail by displaying an estimate. This patch removes that value from the output.

mq: use repo._bookmarks.recordchange instead of repo._bookmarks.write Before this patch, mq was using repo._bookmarks.write. This patch replaces this code with the recommended way of saving bookmarks changes: repo._bookmarks.recordchange.