Bump version to 6.4.2 to mark the merge of TerrainGen branch.
Bump version to 6.4.2 to mark the merge of TerrainGen branch.

Ghostlyr/MinecraftForge,ThiagoGarciaAlves/MinecraftForge,Zaggy1024/MinecraftForge,brubo1/MinecraftForge,dmf444/MinecraftForge,luacs1998/MinecraftForge,Theerapak/MinecraftForge,simon816/MinecraftForge,Vorquel/MinecraftForge,CrafterKina/MinecraftForge,RainWarrior/MinecraftForge,jdpadrnos/MinecraftForge,fcjailybo/MinecraftForge,bonii-xx/MinecraftForge,shadekiller666/MinecraftForge,blay09/MinecraftForge,Mathe172/MinecraftForge,karlthepagan/MinecraftForge,mickkay/MinecraftForge