[MERGE] Show revnos in `bzr tags`

[Martin Pool]

Martin Pool has voted approve.
Status is now: Semi-approved
Comment:
Showing the revnos is a good idea.

At present we don't use the syntax revno:revid, which is a bit like hg 
-- except that they're not linear revnos.  Generally things before the 
colon is a revisionspec, but then they're not allowed to be numeric.  I 
don't mind doing it this way but did want to flag it for other people.

Btw I think reviews of this kind of change may go better if you include 
an example of the output.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070908145111.GA8544%40chistera.yi.org%3E