Better error handling for both RPC and REST calls.
Handle text/html and text/plain differences from both request types correctly.
Proxy response errors as error messages for easier debugging.
Add a test for batched requests where one of the request fails.
Handle errors in binary-encoded requests.
Parse REST responses with JSONBigInt to avoid losing precision. This means that some of the response values will now be strings (e.g. the network difficulty on getDifficulty()).
text/htmlandtext/plaindifferences from both request types correctly.getDifficulty()).