Use cron.pid to get pid number and avoid kill minicron processes. It fixes #3757
Fix multiple issues on unbound advanced options GUI:

- Drop many wrong key assignments to pconfig
- Add missing keys to pconfig
- Deal fine with boolean parameters
- Mark subsystem dirty to require apply button
- Drop calls to enable_change()
- Remove unecessary js function enable_change()
- Fix wrong <input> names
- Change all <select> and text inputs fields to display current value