Implement getRawTransaction

[marius-matioc]

This RPC call is very important.

[roman-khimov]

And I think we already have it implemented as written in the documentation.

For example:

$ curl -d '{ "jsonrpc": "2.0", "id": 5, "method": "getrawtransaction", "params": ["ed5fc511eb946a181625d6e98f535e215c3b95c7406e74bdf726f7f3c709a571"] }' localhost:10332
{"jsonrpc":"2.0","result":"02000240d457afd6dcef6359d73cfab1110fb07709fc950f58ed4b77869fda7c95058600004881c9e2bd8c88b5df3eb6b65fa673611bdfc185eda70418482afc4ea299f6390000000001e72d286979ee6cb1b7e65dfddfb2e384100b8d148e7758de42e4168b71792c608857b5030000000012e00fc1bf09e42bc0a89415a5d55690ade32016014140e8a35e4a7cadd53f6f65515528cf0851af1a9a3ecebc4675535a139c4fa846b7cc462de31432eb7c587e420cb598242ce23a567e959276045cb2839606730cea2321029522d81a487492d3c98ce9267e8960ec4bde8f1e5f0a31ae382867b39808bbf9ac","id":5}
$ curl -d '{ "jsonrpc": "2.0", "id": 5, "method": "getrawtransaction", "params": ["ed5fc511eb946a181625d6e98f535e215c3b95c7406e74bdf726f7f3c709a571"] }' seed5.ngd.network:10332 
{"jsonrpc":"2.0","id":5,"result":"02000240d457afd6dcef6359d73cfab1110fb07709fc950f58ed4b77869fda7c95058600004881c9e2bd8c88b5df3eb6b65fa673611bdfc185eda70418482afc4ea299f6390000000001e72d286979ee6cb1b7e65dfddfb2e384100b8d148e7758de42e4168b71792c608857b5030000000012e00fc1bf09e42bc0a89415a5d55690ade32016014140e8a35e4a7cadd53f6f65515528cf0851af1a9a3ecebc4675535a139c4fa846b7cc462de31432eb7c587e420cb598242ce23a567e959276045cb2839606730cea2321029522d81a487492d3c98ce9267e8960ec4bde8f1e5f0a31ae382867b39808bbf9ac"}

[roman-khimov]

Original bug for this RPC call: #129, PR fixing it: #135. If there are any differences in responses to this call wrt to C# implementation (like #585), please file separate issues, closing this one.