Rename #compose_error to #raise_error and document Middleware::RaiseErrors
Rename Middleware::Ping to Middleware::SignedRequest
Document publicly accessible classes and methods and update Client#poll_request to handle pending errors reasonably
Move ping logic into Requests module
Set Configuration#default_logger level to debug in debug mode
Implement Client#deorbit
Merge pull request #7 from gevans/feature/deorbit

Clean up, documentation, and deorbit implementation