added MagicManaCost constant
improve message
added Carnival Hellsteed
added Chaos Imps
added Dead Reveler
added Gore-House Chainwalker
added Hellhole Flailer
added Rakdos Cackler
added Spawn of Rix Maadi
added Splatter Thug
added Thrill-Kill Assassin
added Grim Roustabout
added test scenario for unleash cards