[MERGE] Change ls-shelf to shelve --list

[Aaron Bentley]

Robert Collins wrote:
> Robert Collins has voted tweak.
> Status is now: Conditionally approved
> Comment:
> +    def run_for_list(self):
> +        tree = WorkingTree.open('.')
> 
> I think WorkingTree.open_containing('.') would be better here;

Done.

> and
> perhaps allow a parameter for a tree to list -
> bzr shelve --list /foo/bar
> would be nice.

I think it would be nice, but I don't want to confuse matters
considering that shelve already accepts a list of files.

Aaron