This is achieved by letting the InfoExtractors instruct its downloader to
process the information dictionary just after extracting the information. As a
consequence, some code is simplified too.
This makes it possible to initialize it with value zero and later let the
trouble() overwrite the value. It simplifies error treatment and paves the way
for the InfoExtracto objects to call process_info() themselves, which should
solve the issues with tor and some other problems.