Tweaks for network and storage (#66)

* Made Encode/Decode message public.

* Added Redis storage driver and made some optimizations for the initialising the blockchain

* removed log lines in tcp_peer

* Added missing comments on exported methods.

* bumped version

pkg/core/storage/helpers.go

@@ -0,0 +1,78 @@
+package storage
+
+import (
+	"encoding/binary"
+	"sort"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// Version will attempt to get the current version stored in the
+// underlying Store.
+func Version(s Store) (string, error) {
+	version, err := s.Get(SYSVersion.Bytes())
+	return string(version), err
+}
+
+// PutVersion will store the given version in the underlying Store.
+func PutVersion(s Store, v string) error {
+	return s.Put(SYSVersion.Bytes(), []byte(v))
+}
+
+// CurrentBlockHeight returns the current block height found in the
+// underlying Store.
+func CurrentBlockHeight(s Store) (uint32, error) {
+	b, err := s.Get(SYSCurrentBlock.Bytes())
+	if err != nil {
+		return 0, err
+	}
+	return binary.LittleEndian.Uint32(b[32:36]), nil
+}
+
+// CurrentHeaderHeight returns the current header height and hash from
+// the underlying Store.
+func CurrentHeaderHeight(s Store) (i uint32, h util.Uint256, err error) {
+	var b []byte
+	b, err = s.Get(SYSCurrentHeader.Bytes())
+	if err != nil {
+		return
+	}
+	i = binary.LittleEndian.Uint32(b[32:36])
+	h, err = util.Uint256DecodeBytes(b[:32])
+	return
+}
+
+// HeaderHashes returns a sorted list of header hashes retrieved from
+// the given underlying Store.
+func HeaderHashes(s Store) ([]util.Uint256, error) {
+	hashMap := make(map[uint32][]util.Uint256)
+	s.Seek(IXHeaderHashList.Bytes(), func(k, v []byte) {
+		storedCount := binary.LittleEndian.Uint32(k[1:])
+		hashes, err := util.Read2000Uint256Hashes(v)
+		if err != nil {
+			panic(err)
+		}
+		hashMap[storedCount] = hashes
+	})
+
+	var (
+		i          = 0
+		sortedKeys = make([]int, len(hashMap))
+	)
+
+	for k, _ := range hashMap {
+		sortedKeys[i] = int(k)
+		i++
+	}
+	sort.Ints(sortedKeys)
+
+	hashes := []util.Uint256{}
+	for _, key := range sortedKeys {
+		values := hashMap[uint32(key)]
+		for _, hash := range values {
+			hashes = append(hashes, hash)
+		}
+	}
+
+	return hashes, nil
+}