all: integrate the freezer with fast sync

* all: freezer style syncing

core, eth, les, light: clean up freezer relative APIs

core, eth, les, trie, ethdb, light: clean a bit

core, eth, les, light: add unit tests

core, light: rewrite setHead function

core, eth: fix downloader unit tests

core: add receipt chain insertion test

core: use constant instead of hardcoding table name

core: fix rollback

core: fix setHead

core/rawdb: remove canonical block first and then iterate side chain

core/rawdb, ethdb: add hasAncient interface

eth/downloader: calculate ancient limit via cht first

core, eth, ethdb: lots of fixes

* eth/downloader: print ancient disable log only for fast sync

core/rawdb/database.go

@@ -24,7 +24,7 @@ import (
 	"github.com/ethereum/go-ethereum/ethdb/memorydb"
 )
 
-// freezerdb is a databse wrapper that enabled freezer data retrievals.
+// freezerdb is a database wrapper that enabled freezer data retrievals.
 type freezerdb struct {
 	ethdb.KeyValueStore
 	ethdb.AncientStore
@@ -51,9 +51,34 @@ type nofreezedb struct {
 	ethdb.KeyValueStore
 }
 
-// Frozen returns nil as we don't have a backing chain freezer.
+// HasAncient returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) HasAncient(kind string, number uint64) (bool, error) {
+	return false, errNotSupported
+}
+
+// Ancient returns an error as we don't have a backing chain freezer.
 func (db *nofreezedb) Ancient(kind string, number uint64) ([]byte, error) {
-	return nil, errOutOfBounds
+	return nil, errNotSupported
+}
+
+// Ancients returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) Ancients() (uint64, error) {
+	return 0, errNotSupported
+}
+
+// AppendAncient returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) AppendAncient(number uint64, hash, header, body, receipts, td []byte) error {
+	return errNotSupported
+}
+
+// TruncateAncients returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) TruncateAncients(items uint64) error {
+	return errNotSupported
+}
+
+// Sync returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) Sync() error {
+	return errNotSupported
 }
 
 // NewDatabase creates a high level database on top of a given key-value data