Progress bar suggestion...

Hi!

I am using PgAdmin III and really like it a lot.
Some SQL queries are longer than other and I would like to suggest to
have a smarter progress bar than the milliseconds counter.

I would suggest (if user enables it) that a progress bar giving the % of
completion of the evaluation steps.
* An "explain" would be run first to know the steps of the query execution.
* The execution would begin and the progress bar (% of completion) for
each step would be updated every seconds or so.

This would keep me (and many other) quieter when executing big updates
or complex queries!

Thanks for the fantastic job!

Christophe