- preprocessor: translate attributes autocomplete_url -> searchUrl, autocomplete_params -> searchOptions, and allow options
- sending search query as URL/GET parameter with default of app: <appname>
- handle searchUrl like allowFreeEntries by adding selected result to select_options via createFreeEntries, as they otherwise get removed by fix_bad_value not finding the value in select_options
- change taglist validation (again) to not validate search values
- still requires changes in application code, as taglist always behaved like multiple=true (returning and expecting an array of values) and did automatically search from client-side for it's initial value(s)
--> maybe more changes are in order to NOT require changing application code
--> fixes editing Sieve rules
