core, eth, rpc: split out block validator and state processor

This removes the burden on a single object to take care of all
validation and state processing. Now instead the validation is done by
the `core.BlockValidator` (`types.Validator`) that takes care of both
header and uncle validation through the `ValidateBlock` method and state
validation through the `ValidateState` method. The state processing is
done by a new object `core.StateProcessor` (`types.Processor`) and
accepts a new state as input and uses that to process the given block's
transactions (and uncles for rewords) to calculate the state root for
the next block (P_n + 1).

eth/helper_test.go

@@ -35,9 +35,7 @@ func newTestProtocolManager(fastSync bool, blocks int, generator func(int, *core
 		db, _         = ethdb.NewMemDatabase()
 		genesis       = core.WriteGenesisBlockForTesting(db, core.GenesisAccount{testBankAddress, testBankFunds})
 		blockchain, _ = core.NewBlockChain(db, pow, evmux)
-		blockproc     = core.NewBlockProcessor(db, pow, blockchain, evmux)
 	)
-	blockchain.SetProcessor(blockproc)
 	chain, _ := core.GenerateChain(genesis, db, blocks, generator)
 	if _, err := blockchain.InsertChain(chain); err != nil {
 		panic(err)