Convert Great Kraken to use persistent effect. (#556)
Convert Great Kraken to use persistent effect. (#556)

Giving Balon stealth is now a persistent effect, getting rid of the
usage for the weird onCardPlayed event.
cryogen/throneteki,DukeTax/throneteki,DukeTax/throneteki,Antaiseito/throneteki_for_doomtown,jeremylarner/ringteki,cryogen/gameteki,cryogen/gameteki,Antaiseito/throneteki_for_doomtown,ystros/throneteki,jeremylarner/ringteki,jeremylarner/ringteki,jbrz/throneteki,jbrz/throneteki,gryffon/ringteki,samuellinde/throneteki,gryffon/ringteki,gryffon/ringteki,cryogen/throneteki,samuellinde/throneteki