"bzr status" in a lightweight checkout

[Andrew Bennetts]

Martin Pool wrote:
[...]
> Alexander wrote:
> 
> > Does `bzr status` check for `tree revision is not up-to-date with branch revision` condition?
> 
> It does, though it could potentially do that by opening only the
> branch not the repository, which may be faster.

I suppose we could allow users to set a “don't check this tree is up-to-date”
flag too.  There's no .bzr/checkout/checkout.conf, but I suppose we could add
one (in a new format?), or perhaps just allow BranchReferenceFormat branches to
have a branch.conf with a single “status_checks_tree_is_up_to_date = false”
line?

-Andrew.