Better check whether a given messageid is in the database
Make several NNTP connections more resillient to errors. Currently very crude implementation, but works.

fixes GH issue #1716
Add PHPdoc for instrumentation to other classes
Add option to specify username and password for push-sabnzbd
Upgrade newznabapi page to utilize new infrastructure of the refactoring code.
Seperate out the scraping bits as we might be able to use them later for other parts of the code.