Added developer instructions to Sphinx documentation.
Series plugin logs verbose when quality requirements are not met.
Developer documentation.
Removed torrage.ws

- Fixes #2029
Merge branch 'master' of https://github.com/Flexget/Flexget into newznab
Refactor discover plugins in order to pass the entry to the search plugins instead of just the title, so the search plugins can speed up the search using information contained in the entry.
Corrected bug that prevented emit_Series from functioning
Used the tvrage api to detect what is the next episode we need instead of generating too many entries
Provided extra information in the entry so search plugins using discover don't need to parse them again.
Made it a search plugins to be used with discover