Add Api to fetch potentially fully spent tx (most recent only)

Using FetchUnSpentTxByShaList only API required unexpected contortions
in btcchain.

db.go

@@ -79,7 +79,15 @@ type Db interface {
 
 	// FetchTxByShaList returns a TxListReply given an array of transaction
 	// hashes.  The implementation may cache the underlying data if desired.
-	FetchUnSpentTxByShaList(txShaList []*btcwire.ShaHash) ([]*TxListReply)
+	// This differs from FetchUnSpentTxByShaList in that it will return
+	// the most recent known Tx, if it is fully spent or not.
+	FetchTxByShaList(txShaList []*btcwire.ShaHash) []*TxListReply
+
+	// FetchUnSpentTxByShaList returns a TxListReply given an array of
+	// transaction hashes.  The implementation may cache the underlying
+	// data if desired. Fully spent transactions will not normally not
+	// be returned in this operation.
+	FetchUnSpentTxByShaList(txShaList []*btcwire.ShaHash) []*TxListReply
 
 	// InsertBlock inserts raw block and transaction data from a block
 	// into the database.  The first block inserted into the database

ldb/dbcache.go

@@ -36,6 +36,13 @@ func (db *LevelDb) fetchBlockBySha(sha *btcwire.ShaHash) (blk *btcutil.Block, er
 	return
 }
 
+// FetchTxByShaList returns the most recent tx of the name fully spent or not
+func (db *LevelDb) FetchTxByShaList(txShaList []*btcwire.ShaHash) []*btcdb.TxListReply {
+	// until the fully spent separation of tx is complete this is identical
+	// to FetchUnSpentTxByShaList
+	return db.FetchUnSpentTxByShaList(txShaList)
+}
+
 // FetchUnSpentTxByShaList given a array of ShaHash, look up the transactions
 // and return them in a TxListReply array.
 func (db *LevelDb) FetchUnSpentTxByShaList(txShaList []*btcwire.ShaHash) []*btcdb.TxListReply {

sqlite3/sqlitedbcache.go

@@ -131,6 +131,13 @@ func (db *SqliteDb) insertBlockCache(sha *btcwire.ShaHash, blk *btcutil.Block) {
 	bc.blockMap[blkObj.sha] = &blkObj
 }
 
+// FetchTxByShaList returns the most recent tx of the name fully spent or not
+func (db *SqliteDb) FetchTxByShaList(txShaList []*btcwire.ShaHash) []*btcdb.TxListReply {
+	// until the fully spent separation of tx is complete this is identical
+	// to FetchUnSpentTxByShaList
+	return db.FetchUnSpentTxByShaList(txShaList)
+}
+
 // FetchUnSpentTxByShaList given a array of ShaHash, look up the transactions
 // and return them in a TxListReply array.
 func (db *SqliteDb) FetchUnSpentTxByShaList(txShaList []*btcwire.ShaHash) []*btcdb.TxListReply {