* Basic support for negative searches with parentheses
* `!((author:Alice intitle:hello) OR (author:Bob intitle:world))`
* `(author:Alice intitle:hello) !(author:Bob intitle:world)`
* `!(S:1 OR S:2)`
* Minor documentation / comment
* Remove syslog debug line
* New possibility to invoke user queries from a search expression
From the search field: `S:"My query"`.
Can be combined with other filters such as `S:"My query" date:P3d` as long as the user queries do not contain `OR`.
A use-case is to have an RSS filter with a stable address or an external API call with the ability to update the user query.
* Draft of parenthesis logic
* More draft
* Working parenthesis (a OR b) (c OR d)
* Working (A) OR (B)
* Support nested parentheses + unit tests + documentation
* search:MySearch and S:3
* Fix some search expressions
* Fix decoding bug when using quotes to search free text containing some spaces such as `"ab cd"`
* Fix use of `-` wrongly triggering a negative search in e.g. `ab-cd`
* Fix edge cases
* A couple of tests
