subrepo: allow a representation of the working directory subrepo
Some code cannot handle a subrepo based on the working directory (e.g.
sub.dirty()), so the caller must opt in. This will be useful for archive, and
perhaps some other commands. The git and svn methods where this is used may
need to be fixed up on a case by case basis.
When Mercurial accepts more than one revision, they may be specified
individually, or provided as a topologically continuous range,
separated by the ":" character.
The syntax of range notation is [BEGIN]:[END], where BEGIN and END are
revision identifiers. Both BEGIN and END are optional. If BEGIN is not
specified, it defaults to revision number 0. If END is not specified,
it defaults to the tip. The range ":" thus means "all revisions".
If BEGIN is greater than END, revisions are treated in reverse order.
A range acts as a closed interval. This means that a range of 3:5
gives 3, 4 and 5. Similarly, a range of 9:6 gives 9, 8, 7, and 6.