adding socket obj to error logging (should not only help match up requests with errors, but will also let us know when an event occurred and a socket was not available).
Better error handling in main parser

Fixes issue #34. When an error occurs while parsing headers, it is sent
off to the main-error-handler function, and the request is marked with
an error so the finished/body callbacks no longer process it.

When this happens, it's important for the app itself to send back an
error notice to the client, as Wookie will not do this for you.