Orphans for V2

[kozross]

Closes #681. This will need to be updated in PR #679 for V3 versions of the types in question.

[SeungheonOh]

LGTM, some questions only

[bladyjoker]

I'm not sure what happens when you generate some TxInfo fields

data TxInfo = TxInfo
    { txInfoInputs          :: [TxInInfo] -- ^ NON EMPTY Map TxOutRef TxInInfo (NOT A LIST)
    , txInfoReferenceInputs :: [TxInInfo] -- ^ Same as above
    , txInfoOutputs         :: [TxOut] -- ^ Anything goes but Value must have positive ADA
    , txInfoFee             :: Value -- ^ This MUST be ONLY ADA
    , txInfoMint            :: Value -- ^ This contains 0 ADA
    , txInfoDCert           :: [DCert] -- ^ Not sure but I suspect this is also a Map of sorts
    , txInfoWdrl            :: Map StakingCredential Integer
    , txInfoValidRange      :: POSIXTimeRange -- ^ End MUST be after begginning (shock and disbelief).
    , txInfoSignatories     :: [PubKeyHash] -- ^ This is NOT a LIST this is a Set PubKeyHash
    , txInfoRedeemers       :: Map ScriptPurpose Redeemer
    , txInfoData            :: Map DatumHash Datum
    , txInfoId              :: TxId
    } 

[bladyjoker]

TxInfo list/map/set invariants are missing right? You want to add these in some other PR?