core, miner, tests: renamed state methods

* Update => SyncIntermediate
* Added SyncObjects

SyncIntermediate only updates whatever has changed, but, as a side
effect, requires much more disk space.

SyncObjects will only sync whatever is required for a block and will not
save intermediate state to disk. As drawback this requires more time
when more txs come in.

core/block_processor.go

@@ -77,7 +77,7 @@ func (self *BlockProcessor) ApplyTransaction(coinbase *state.StateObject, stated
 	}
 
 	// Update the state with pending changes
-	statedb.Update()
+	statedb.SyncIntermediate()
 
 	usedGas.Add(usedGas, gas)
 	receipt := types.NewReceipt(statedb.Root().Bytes(), usedGas)
@@ -243,7 +243,7 @@ func (sm *BlockProcessor) processWithParent(block, parent *types.Block) (logs st
 
 	// Commit state objects/accounts to a temporary trie (does not save)
 	// used to calculate the state root.
-	state.CleanUpdate()
+	state.SyncObjects()
 	if header.Root != state.Root() {
 		err = fmt.Errorf("invalid merkle root. received=%x got=%x", header.Root, state.Root())
 		return