Support nil pointers for Binary.

If the thing does not already have a typebyte declared,
a fake one will be given (0x01).
A TypeByte of 0x00 is reserved for nil things.
No nil-dogs.

types/tx.go

@@ -76,7 +76,7 @@ type TxInput struct {
 	Amount    uint64            // Must not exceed account balance
 	Sequence  uint              // Must be 1 greater than the last committed TxInput
 	Signature account.Signature // Depends on the PubKey type and the whole Tx
-	PubKey    account.PubKey    // Must not be nil, may be PubKeyNil.
+	PubKey    account.PubKey    // Must not be nil, may be nil
 }
 
 func (txIn *TxInput) ValidateBasic() error {

types/vote.go

@@ -40,9 +40,9 @@ type Vote struct {
 
 // Types of votes
 const (
-	VoteTypePrevote   = byte(0x00)
-	VoteTypePrecommit = byte(0x01)
-	VoteTypeCommit    = byte(0x02)
+	VoteTypePrevote   = byte(0x01)
+	VoteTypePrecommit = byte(0x02)
+	VoteTypeCommit    = byte(0x03)
 )
 
 func (vote *Vote) WriteSignBytes(w io.Writer, n *int64, err *error) {