Make it easier to add new parameters later, get rid of redundant code, clean
up, align between httpd_xxx modules and introduce new bugs. Yes, the refactor
got a bit out of hand.
In preparation for the new endpoints the following refactorings where
done in lastfm.c:
- Initialize lastfm.c in main.c instead of on first scrobble attempt
(necessary to retrieve the correct lastfm status)
- Return error messages if login attempt failed
- Add api function for status and logout
- Notify about Last.fm status changes
Unrelated changes in lastfm.c are:
- Refactoring of request_post
- Add request parameters sorted alphabetically and remove calling the
sort method in request_post
