evm: refactor state transition (#41)

* evm: keeper statedb refactor

* keeper: implement stateDB account, balance, nonce and suicide functions

* keeper: implement stateDB code and iterator functions

* keeper: implement stateDB log and preimage functions

* update code to use CommitStateDB

* tests updates

* journal changes (wip)

* cache fields

* journal and logs

* minor cleanup

* evm: state transition refactor

* evm: unpack revert errors

* evm: update state transition (wip)

* evm: remove journal related changes

* evm: delete empty account code and storage state

* update gas limit

* evm: header hash to/from context

* evm: minor params and state transition changes

* ante: state transition changes

* ante: refactor default sig gas consumer

* ante: ignore gas costs from ops other than intrinsic gas

* ante: CanTransferDecorator

* evm: refund gas

* update comments

* state transition comments

* ante: CanTransfer and AccessList decorator tests

* evm: cleanup state transition

* ignore nonce increment during ante handler on contract creation

* fix ante tests

* more test fixes

types/errors.go

@@ -18,9 +18,6 @@ var (
 	// ErrInvalidChainID returns an error resulting from an invalid chain ID.
 	ErrInvalidChainID = sdkerrors.Register(RootCodespace, 3, "invalid chain ID")
 
-	// ErrVMExecution returns an error resulting from an error in EVM execution.
-	ErrVMExecution = sdkerrors.Register(RootCodespace, 4, "error while executing evm transaction")
-
 	// ErrMarshalBigInt returns an error resulting from marshaling a big.Int to a string.
 	ErrMarshalBigInt = sdkerrors.Register(RootCodespace, 5, "cannot marshal big.Int to string")