GetPCRank did not handle ignored explicit references
Can be easily tested with the "GetPcRank" instruction.
Error: Object 'player' not found (const)
Apparently the ID of the explicit reference is overwriting the function argument.
(RM-1767 from redmine: created on 2014-08-06 by scrawl ., , closed on 2014-08-24 by Marc Zinnschlag, duplicates #1766 (closed))