checkin - Viewer does better regression testing

[karnaze]

Viewer now delays (i.e. -d option) before writing the regression data
for a page. Before it was delaying after writing the data. This gives
incremental reflow more time on some pages and eliminates the bogus bbox
differences. Viewer can now also accept a delay inside the file list
(e.g. delay:=2 on a line would set the delay to 2 seconds for subsequent
pages).