[MERGE] optimize annotate

[Nicholas Allen]

> No, you don't.  He's talking about files.  He's right that we shouldn't
> keep large numbers of file versions in memory.  But that's beside the
> point, because it's not what my change does.
>
> I'm talking about revisions, not file versions.  Revisions store the
> commit log, the committer name, the time-of-commit, and that sort of
> thing.  They are ~1K in size, no matter how big your files are.  So
> keeping lots and lots of revisions in memory is completely fine.

Cool - thought I must have misunderstood ;-)

Nick