Move logger to own package; clean up apiserver to use serve mux.
Merge pull request #475 from lavalamp/httpLogger

Move logger to own package; clean up apiserver to use serve mux.
Make RESTful operations return 404 Not Found when the target resource
does not exist.

In the original implementation, GET, DELETE and PUT operations on
non-existent resources used to return 500 but not 404.