[z1956] Add support for Creature List of Entry in Range grid searcher

Signed-off-by: Schmoozerd <schmoozerd@scriptdev2.com>
Signed-off-by: Nighoo <nighoo@gmail.com>

(cleaned version of 951b82b)

(based on commit [s1546] - 19b6238)
[z1957] Add additional check for game_events, invalid occurence

Signed-off-by: Schmoozerd <schmoozerd@scriptdev2.com>
Signed-off-by: Nighoo <nighoo@gmail.com>

(based on 641e7ce7b4ebc4)

(cleaned version of 76afaeb)

(based on commit [s1547] - b53fde7)