integrate blockpool into eth

- remove blockpool code
- remove blockpool integration test (kinda embarrassing)
- remove errors.go

eth/backend.go

@@ -7,6 +7,7 @@ import (
 	"path"
 	"strings"
 
+	"github.com/ethereum/go-ethereum/blockpool"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
@@ -117,7 +118,7 @@ type Ethereum struct {
 	blockProcessor *core.BlockProcessor
 	txPool         *core.TxPool
 	chainManager   *core.ChainManager
-	blockPool      *BlockPool
+	blockPool      *blockpool.BlockPool
 	whisper        *whisper.Whisper
 
 	net      *p2p.Server
@@ -185,7 +186,7 @@ func New(config *Config) (*Ethereum, error) {
 
 	hasBlock := eth.chainManager.HasBlock
 	insertChain := eth.chainManager.InsertChain
-	eth.blockPool = NewBlockPool(hasBlock, insertChain, ezp.Verify)
+	eth.blockPool = blockpool.New(hasBlock, insertChain, ezp.Verify)
 
 	netprv, err := config.nodeKey()
 	if err != nil {
@@ -220,7 +221,7 @@ func (s *Ethereum) Name() string                         { return s.net.Name }
 func (s *Ethereum) ChainManager() *core.ChainManager     { return s.chainManager }
 func (s *Ethereum) BlockProcessor() *core.BlockProcessor { return s.blockProcessor }
 func (s *Ethereum) TxPool() *core.TxPool                 { return s.txPool }
-func (s *Ethereum) BlockPool() *BlockPool                { return s.blockPool }
+func (s *Ethereum) BlockPool() *blockpool.BlockPool      { return s.blockPool }
 func (s *Ethereum) Whisper() *whisper.Whisper            { return s.whisper }
 func (s *Ethereum) EventMux() *event.TypeMux             { return s.eventMux }
 func (s *Ethereum) Db() ethutil.Database                 { return s.db }