add http middleware, add option to use custom mux, improved logger kvs

service/mux.go

@@ -0,0 +1,15 @@
+package service
+
+import (
+	"net/http"
+
+	"github.com/justinas/alice"
+)
+
+type ServeMux interface {
+	ServeHTTP(http.ResponseWriter, *http.Request)
+	Handle(pattern string, handler http.Handler)
+	HandleFunc(pattern string, handler func(http.ResponseWriter, *http.Request))
+}
+
+type Middleware = alice.Constructor