Fix Tx extension options & middleware issues

[roysc]

Resolves #37

[roysc]

Gas limit issue is fixed, but now transactions seem to not be indexed under the correct hash in tendermint and the receipts can't be found:

1:09AM DBG eth_sendTransaction args="TransactionArgs{From:0x516F194C25997524595C51dAd53740F0A4B19C8c, To:0xc94770007dda54cF92009BFF0dE90c06F603a09f, Gas:<nil>, Nonce:<nil>, Data:<nil>, Input:<nil>, AccessList:<nil>}" client=json-rpc
1:09AM DBG estimate gas usage automatically gas=0x5208 module=evm-backend
1:09AM DBG inserted good transaction height=6 module=mempool num_txs=1 priority=0 tx=4368DA503494F1826DA2E3C560BC947A444CAF3F405EFACF60C10FE26AB5B6AC version=v1
1:09AM DBG Served eth_sendTransaction conn=127.0.0.1:51664 duration=130.406784 module=geth reqid=1
1:09AM DBG no available peers to send request to, waiting...
1:09AM DBG eth_getTransactionReceipt client=json-rpc hash=0x796d5637a474d307e8de22076e2b08e1bc6ba60ecbbab339b9da8d07ff50b65d
1:09AM DBG tx not found error="ethereum tx not found for hash 0x796d5637a474d307e8de22076e2b08e1bc6ba60ecbbab339b9da8d07ff50b65d" client=json-rpc hash=0x796d5637a474d307e8de22076e2b08e1bc6ba60ecbbab339b9da8d07ff50b65d

Wondering if it's related to tendermint/tendermint#6539 - SHA => RLP conversion?

[gsk967]

@roysc LGTM