Add NewWithConfig init function to api/server.go (#192)

* add NewWithConfig function

* cleanup

api/server.go

@@ -56,6 +56,16 @@ func New(log *logp.Logger, mux *http.ServeMux, c *config.C) (*Server, error) {
 	if err != nil {
 		return nil, err
 	}
+	return new(log, mux, cfg)
+}
+
+// NewFromConfig creates a new API server from the given Config object.
+func NewFromConfig(log *logp.Logger, mux *http.ServeMux, cfg Config) (*Server, error) {
+	return new(log, mux, cfg)
+}
+
+// new creates the server from a config struct
+func new(log *logp.Logger, mux *http.ServeMux, cfg Config) (*Server, error) {
 	srv := &http.Server{ReadHeaderTimeout: cfg.Timeout}
 	l, err := makeListener(cfg)
 	if err != nil {