condensediffs now shows more information on the progress of the

conversion of diffs. Along with the existing percentage, it will also

now show the number of processed items, how many there are total, and

the estimated time to completion.
Since the estimated time to completion is based on the average time

taken per item, and the number of items, the estimate becomes more

accurate over time. Instead of showing some useless numbers up-front, we

wait 30 seconds until we show the estimate. From my testing, this

appears to be a a good number, as the estimate settled around that point

in the databases I used.
This helps give administrators an idea as to how long the operation will

take, which is useful for knowing whether to keep it going or to abort

and finish later.

Ran this with many diffs and databases of different sizes.