Check videomap for duplicate entries

[Marcel510]

When working at LTBA I added some lines twice by mistake, after that the playing the airport felt pretty laggy. Therefore it would be good if the validator checks the entries for duplicates.

I'd also like to mention that this:
["AAAAAAAAAA", "BBBBBBBBBB", "CCCCCCCCCC", "DDDDDDDDDD"]
Is the same as this:
["CCCCCCCCCC", "DDDDDDDDDD", "AAAAAAAAAA", "BBBBBBBBBB"]
If possible this should be also taken into account