Include the calculated nonce in the receipt

The receipt at the moment doesn't contain the nonce. As the nonce can be automatically calculated by ethconnect, it would be helpful to include it in the response.

```json
{
"blockHash": "0x72c99b65904884e175506bc2301fef7de6e8e36454cf724993d5133bfabb4548",
"blockNumber": "5188",
"blockNumberHex": "0x1444",
"cumulativeGasUsed": "268170",
"cumulativeGasUsedHex": "0x4178a",
"from": "0xc07f8826b4fe5fc4e63724ad828c13f57e98852b",
"gasUsed": "26817",
"gasUsedHex": "0x68c1",
"headers": {
"id": "1f1cbac5-ad18-45b1-731b-21fc6b6f5459",
"requestId": "7f207713-fe7e-46ec-63a9-b52f351eea4a",
"requestOffset": "zzv7ezplvf-zzi7p59v1e-requests:0:46325",
"timeElapsed": 20.591966662,
"timeReceived": "2018-07-23T17:50:02Z",
"type": "TransactionSuccess"
},
"status": "1",
"statusHex": "0x1",
"to": "0xe1cda5bf18c1693d46c352a13154a90e55f8c179",
"transactionHash": "0x49c742b3a92d89086cd46c91145da22d67d77f4bc41bdb9d67ad3c10236f9a00",
"transactionIndex": "9",
"transactionIndexHex": "0x9"
}
```