[Libguestfs] [PATCH v2] Add progress bars

[Richard Jones]

This is an updated and extended version of the original patch:
https://www.redhat.com/archives/libguestfs/2010-August/msg00163.html

This adds OCaml and Perl bindings (both tested), support for
progress bars in virt-resize, and adds progress notifications
to a number of the simpler commands.

Still to do is to add progress messages to more commands.  There
are still a few commands which would be fairly easy (eg. download and
some t*-out commands).  There are many others where implementing
progress messages will be quite a lot more complex.

Note: I have changed the default frequency of messages.  They are
now sent after two seconds, and every 1/3rd of a second thereafter.
This makes the progress bars smoother and avoids aliasing effects
when displaying time left in seconds.

Note (2): All known comments about the previous patches have been
incorporated.

Rich.