Retrieve 'thumbnail' and 'folders' properties for each post.
'thumbnail' (#1284):
- Preview image used for search results, writing posts, music, etc.
- Filename format: <post_id>@600-<directory_containing_full_image>.jpg
'Folders' (related to #1817):
- A list of all gallery folders containing this post
- Folder name format: [<folder_category> - ]<folder_name>
- Only works on new layout; old layout does not show folders, so list will be empty
A test is included for each property.
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()'.
An extra field is collected when paginating favorites, and saved to
a temporary cache variable. This field is identical for both the old
and the new page layouts for FurAffinity, but can only be collected
during pagination, hence the cache variable. Other FurAffinity
extractors should be unaffected by this change.
Fetch 'title' and 'artist' metadata from a different location,
since for posts with an empty title the <title> element is
completely empty and does not contain the artist's name.
'/?&#' -> '/?#' and '?&#' -> '?#'
According to https://www.ietf.org/rfc/rfc3986.txt, URLs are
"organized hierarchically" by using "the slash ("/"), question
mark ("?"), and number sign ("#") characters to delimit components"
