CI build setup is fixed, email notifications improved

Hi all,

Rails CI build on http://cruisecontrolrb.thoughtworks.com had a
problem yesterday, when Ruby started segfaulting somewhere inside
Rake. I fixed it last night... by recompiling Ruby on server (?!)

Also, some people here asked to include changelog and a summary of
Test::Unit errors in the email notifications CruiseControl.rb sends.
It's done.

If you ever see that the CI build is failing when it shouldn't be
(because of a problem with the server), do not hesitate to send me a
heads-up message.

Your friendly build monkey,
Alex

Thanks for the tuneup, Alex!

jeremy