Introduce an 'initialize()' function that does the actual init
(session, cookies, config options) and can called separately from
the constructor __init__().
This allows, for example, to adjust config access inside a Job
before most of it already happened when calling 'extractor.find()'.
- move HTML request for post pages into its own function
- move gelbooru_v02.py notes extraction to gelbooru.py
since it only works there
- clean up some code
Gelbooru only allows to retrieve the latest 20k posts for a tag search.
Add 'id:<N' to the search tags to work around that limitation, where N
is the ID of the last retrieved post.
http://gelbooru.me/index.php?page=forum&s=view&id=1467
* [booru] add an option to extract notes (currently implemented only for gelbooru)
* appease linter
* [gelbooru] rename "text" to "body" in note extraction
* add a code comment about reusing return value of _extended_tags
