[sugar] add xcompmgr to the olpc-development stream builds

[Bernie Innocenti]

Erik Garrison wrote:
> I have attached a patch to bin/sugar.in which launches xcompmgr prior to
> starting matchbox.  I have not tested this as I don't have a recent
> build of Sugar to test on an XO.  In 8.2 it was possible to achieve the
> same result by adding a hook to main.py.

On IRC I said we'd be better off moving this to olpc-session, so the
Sugar codebase should stay clear of platform-specific support.

However, I noticed we also run the window manager from there and it
would make a lot of sense to keep the composing manager next to it.
Some modern window managers even do both things.

Perhaps these things should be moved to olpc-session?  Either way, it
 could be done at a later point with a separate patch.

-- 
   // Bernie Innocenti - http://www.codewiz.org/
 \X/  Sugar Labs       - http://www.sugarlabs.org/