Tighten up expectation, make expected files consistent.

Just expecting the parsed file to include the expected one would mean
success in the case where nothing has been folded. Tighten up the
expectation, and add quoting placeholders to expected files that didn't
have them.
Handle gmail-style quoting from the HTML part of a mail.

We already handled this type of quoting when coming directly from a text
part of a mail, but when we choose the HTML part as the main part and
then convert it to text, the 'On [date] <email> person said:' part can
get split over two lines.
Merge branch 'feature/1269-improve-quoting-recognition' into rails-3-develop