rpc: trace_callMany

[domiwei]

Record changes to balance/code/nonce/storage using a kind of tracer as caller requests a simulation for series of transactions.

Sample output:

{
  "blockNumber": <latest block number>,
  "traceResult": [
      {
           "stateDiff": {
                "balance": {
                      "from": "0x123",
                      "to": "0x456",
                 }
               "nonce": {
                      "from": "0x987",
                      "to": "0x990",
                 }
               "code": {
                    "from": "",
                    "to": "407d73d8a49eeb85d32cf465507dd71d507100c1407d73d8a49eeb85d32cf465507dd71d507100c1",
               }
               "storage": {
                     "0x34247832969": {
                           "from": ... ,
                           "to": ... ,
                     }
                    "0x89073982342": {
                           "from": ... ,
                           "to": ... ,
                     }
               }
           }
      }
      {
           "stateDiff": {
                "balance": {
                      "from": "0x55632",
                      "to": "0x456",
                 }
               "nonce": {
                      "from": "0x897",
                      "to": "0x898",
                 }
               "code": "=",
               "storage": {}
           }
      }
  ]
}