Fix encoding of last line
* src/mimedataprovider.cpp (get_body, get_html_body): Don't append raw undecoded data anymore. (MimeDataProvider::finalize): New. Parse the last unfinished data. * src/parsecontroller.cpp (ParseController::parse): Call finalize.
Before this a quoted printable line without a line feed at the
end would not be decoded. Leading to a broken display.
(cherry picked from commit a0671ccbb477e31d25547532004fa6fd16a29f78)