[abc] overnight tests

I've just reworked the overnight tests a bit. Features added:

  - Summarise changes in subject line of email
  - Run reweaving tests in Oxford, since Ondrej's seem to have to stopped
    running. As before, these are against the current set of "standard"
    results, not against the previous reweaving results.

We'd like to run -O3 tests automatically too, but there's still the issue
of needing to inform abc what the main class is, which means we need to
put this information into the tests somehow. I guess another field in the
XML file is the way to go.

Ganesh
Received on Thu Aug 17 22:32:33 2006