* Add example for before & before_ operator
* Add formal test for both operators
* Add before operator to supported list
* Add before_ operator to wrong behaviour list
* Add example for eventually! operator
* Add formal test for eventually! operator (throws an error during synthesis)
* Add eventually! to supported list with hint to failing synthesis
* Add example for next_event[n] operator
* Add formal test for next_event[n] operator
* Add next_event[n] to supported list
* Add next_event_a[n] & next_event_e[n] to unsupported list