Phil has a changeset on reviewboard.eng with the following
format:
> Changes:
> blah blah blah
>
> Details:
> blah blah

Apparently perforce actually shows "Changes: blah blah blah" as
the summary line, so it makes sense to support this.  This change
will try to find '\n\n' within the first 100 characters of a
changeset description.  If it finds it, it'll take everything up
to that, replace newlines with spaces, and use that as the summary.

Added a sample changeset in testdata, a unit test, and ran
all tests.