feature: batch request for electrum

[lord2anil]

Modified the handle_message function of electrum_protocol for handling batch requests

closes #107

[Davidson-Souza]

Hi @lord2anil thank you for your pr. Did you test this with some wallet? I'm not sure how do we tell wallets that we support batching, but I think we need to do something

[lord2anil]

Okay, I will test it and notify you once I am done.

[lord2anil]

Hi, I tested the API, with this payload (send data as vector)
payload = [ { 'jsonrpc': '2.0', 'method': 'method1', 'params': [], 'id': 1 }, { 'jsonrpc': '2.0', 'method': 'method2', 'params':[], 'id': 2 }, { 'jsonrpc': '2.0', 'method': 'method3', 'params': [], 'id': 3 } ]
And it is working for batch requests.

for a single request
the payload is
payload = { 'method': method, 'params': [ ], 'jsonrpc': '2.0', 'id': '0', }

[Davidson-Souza]

ACK 7ccb885