AuthServiceProxy is an improved version of python-jsonrpc.

It includes the following generic improvements:

- HTTP connections persist for the life of the AuthServiceProxy object
- sends protocol 'version', per JSON-RPC 1.1
- sends proper, incrementing 'id'
- uses standard Python json lib

It also includes the following bitcoin-specific details:

- sends Basic HTTP authentication headers
- parses all JSON numbers that look like floats as Decimal