Metrics improvements

- Label graphs by their duration, not update period
- Extend to 60 units so they are either 10 minutes or an hour of data
- Improvements to retention information
- Change javascript calculations, fixes #9 (I hope)

web/root_controller.go

@@ -1,6 +1,7 @@
 package web
 
 import (
+	"github.com/jhillyerd/inbucket/config"
 	"net/http"
 )
 
@@ -11,7 +12,9 @@ func RootIndex(w http.ResponseWriter, req *http.Request, ctx *Context) (err erro
 }
 
 func RootStatus(w http.ResponseWriter, req *http.Request, ctx *Context) (err error) {
+	retentionMinutes := config.GetDataStoreConfig().RetentionMinutes
 	return RenderTemplate("root/status.html", w, map[string]interface{}{
 		"ctx": ctx,
+		"retentionMinutes": retentionMinutes,
 	})
 }