Please update your evolve extension: obsmarker exchange improvement

[Pierre-Yves David]

Dear early evolve user,

If you are currently using mercurial default head (also known as @ 
bookmark) I invite you to update to the current default head of the 
mutable-history repo.

This will you access to the following improvement regarding obsolescence 
markers exchange:

1. push will only push markers relevant to the pushed subset,
2. pull will only pull markers relevant to the pushed subset
    (if you also upgrade your server),
3. tons of debug about regarding the obsmarkers exchanges process,
4. Nice progress bar while pushing obsmarkers. (for old server only)
5. a slightly faster exchange of markers (a few tens percents)

This should not have a significant impact on the speed of the exchange 
are we are still pushing too much data. (but now you have a progress bar 
during push). The next step is to improve the amount of data we send. 
But where are not there yet.

The exchange strategy now in effect is explained on the associated wiki 
page:

  http://mercurial.selenic.com/wiki/ObsolescenceMarkersExchange

I recommend running `hg debugrecordpruneparents` once, right after 
update for a better result. This will update your existing prune markers 
with parents information when possible.

Please report any misbehavior or crash.

-- 
Pierre-Yves