[release/1.3.4] parmas, crypto, core, core/vm: homestead consensus protocol changes

* change gas cost for contract creating txs
* invalidate signature with s value greater than secp256k1 N / 2
* OOG contract creation if not enough gas to store code
* new difficulty adjustment algorithm
* new DELEGATECALL op code

Conflicts:
	core/vm/environment.go
	crypto/crypto.go
	crypto/secp256k1/secp256.go
	eth/api.go

core/bench_test.go

@@ -82,7 +82,7 @@ func genValueTx(nbytes int) func(int, *BlockGen) {
 	return func(i int, gen *BlockGen) {
 		toaddr := common.Address{}
 		data := make([]byte, nbytes)
-		gas := IntrinsicGas(data)
+		gas := IntrinsicGas(data, false, false)
 		tx, _ := types.NewTransaction(gen.TxNonce(benchRootAddr), toaddr, big.NewInt(1), gas, nil, data).SignECDSA(benchRootKey)
 		gen.AddTx(tx)
 	}