* Make scan_query, parse_query, normalize_query into instance methods
instead of class methods. This is to a) clean up the API and b)
prepare for moving certain tag utility methods into PostQueryBuilder.
* Fix a few cases where a caller used scan_query when they should have
used split_query or parse_tag_edit.
* Support negating the child: and embedded: metatags.
* Fix approver:<any|none>, disapproved:<reason>, commentary:<type> being
case sensitive.
* Fix child:garbage, locked:garbage, embedded:garbage returning all
posts instead of no posts.
* Fix not being able to use source:, locked:, or -id: twice in the same
search.
* Fix not being able to use the status: metatag twice in the same search.
* Fix status:active excluding banned posts.
* Fix status:garbage returning all posts.
Support exclusive ranges for numeric metatags. For example, `id:5...10`
is equivalent to `id:>=5 id:<10`. Useful for splitting searches into id
ranges without the endpoints overlapping: id:100...200, id:200...300,
id:300...400.
Support using the same numeric-valued metatag twice in the same search.
Numeric-valued metatags are those taking an integer, float, filesize, or
date argument. Previously using the same metatag twice would cause the
second metatag to overwrite the first metatag.
Examples:
* "id:>5 id:<10"
* "width:>500 width:<1000"
* "date:>2019-01-01 date:<2020-01-01"
Support using quoted values with all metatags. For example: user:"blah blah",
pool:"blah blah", commentary:"blah blah", etc. Things like rating:"safe",
id:"42" also work. Both single and double quotes are supported.
Also make the status: and rating: metatags fully free. Before only
status:deleted and rating:s were free.
