Moved logging to state, proper structured block

* Moved logs to state so it's subject to snapshotting
* Split up block header
* Removed logs from transactions and made them receipts only

ethpipe/vm_env.go

@@ -34,7 +34,7 @@ func (self *VMEnv) BlockHash() []byte      { return self.block.Hash() }
 func (self *VMEnv) Value() *big.Int        { return self.value }
 func (self *VMEnv) State() *ethstate.State { return self.state }
 func (self *VMEnv) GasLimit() *big.Int     { return self.block.GasLimit }
-func (self *VMEnv) AddLog(vm.Log)          {}
+func (self *VMEnv) AddLog(ethstate.Log)    {}
 func (self *VMEnv) Transfer(from, to vm.Account, amount *big.Int) error {
 	return vm.Transfer(from, to, amount)
 }