Made KeyTag and FieldType V type argument covariant (so that records are covariant - required for Product toRecord)
Made KeyTag and FieldType V type argument covariant (so that records are covariant - required for Product toRecord)

isaka/shapeless,joescii/shapeless,lukasz-golebiewski/shapeless,khronnuz/shapeless,fthomas/shapeless,malcolmgreaves/shapeless,roberth/shapeless,triggerNZ/shapeless,TomasMikula/shapeless,tek/shapeless,lambdista/shapeless,liff/shapeless,alexarchambault/shapeless,wheaties/shapeless,clhodapp/shapeless,milessabin/shapeless,notxcain/shapeless,Atry/shapeless