Merge lp://staging/~mwhudson/loggerhead/clean-up-inventory-view into lp://staging/loggerhead

Third time lucky?

Hi Martin (probably :),

This branch cleans up the inventory view considerably, showing the way
I'd like to go with loggerhead over the next few days. It's not got as
far as removing all use of history.py, at all, but it moves a chunk of
bzrlib usage closer to the action.

I also cleaned up (well, added) the input validation and added a fair
number of tests.

Cheers,
mwh

Hi Michael,

This looks very good, I really appreciate the cleanup, and it looks good to merge.

Just one question:

> === modified file 'loggerhead/controllers/inventory_ui.py'
> @@ -85,7 +141,7 @@
> .
> change = history.get_changes([ revid ])[0]
> # If we're looking at the tip, use head: in the URL instead
> - if revid == history.last_revid:
> + if revid == branch.last_revision():

Isn't "revision" a little ambiguous? Or are we going to assume revision == revid, and revno == revno?