Currently the `getnetworkinfo` returns something like: 

```
"localservices": "0000000000000449",
```

Manually parsing this consistently gives me a headache (see also https://github.com/sipa/bitcoin-seeder/pull/77).

It would be useful to parse this and show the right combination of `NODE_NETWORK`, `NODE_GETUTXO`, `NODE_BLOOM`, `NODE_WITNESS`, `NODE_NETWORK_LIMITED` and `NODE_COMPACT_FILTERS`. In addition the help text for `getnetworkinfo` could be expanded to mention the right BIP numbers for known flags.

There is some ad hoc parsing to populate e.g. `localrelay`, etc (?).  Their help text could also refer back to `NODE_GETUTXO`.

See also: https://en.bitcoin.it/wiki/Protocol_documentation#Network_address
{
    return ParseHashV(find_value(o, strKey), strKey);
}
std::vector<unsigned char> ParseHexV(const UniValue& v, std::string strName)
{
    std::string strHex;
    if (v.isStr())
        strHex = v.get_str();
    if (!IsHex(strHex))
        throw JSONRPCError(RPC_INVALID_PARAMETER, strName+" must be hexadecimal string (not '"+strHex+"')");
    return ParseHex(strHex);
}
std::vector<unsigned char> ParseHexO(const UniValue& o, std::string strKey)
{
    return ParseHexV(find_value(o, strKey), strKey);
}
std::string HelpExampleCli(const std::string& methodname, const std::string& args)
{
    return "> bitcoin-cli " + methodname + " " + args + "\n";
}
std::string HelpExampleRpc(const std::string& methodname, const std::string& args)
{
    return "> curl --user myusername --data-binary '{\"jsonrpc\": \"1.0\", \"id\":\"curltest\", "
        "\"method\": \"" + methodname + "\", \"params\": [" + args + "] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/\n";
}
CPubKey HexToPubKey(const std::string& hex_in)