Merge branch 'master' into develop

scripts/prepareServiceWorker.ts

@@ -9,12 +9,14 @@ class PrepareServiceWorker extends Script {
 
     public async main() {
         const v = Constants.vNumber
+        const date = new Date().getTime()
         writeFileSync(
             "./src/service-worker/SWGenerated.ts",
             [
                 "export class SWGenerated {",
                 "// generated by scripts/prepareServiceWorker.ts",
                 "static vNumber = " + JSON.stringify(v),
+                "static buildTime = " + date,
                 "}",
             ].join("\n"),
             "utf8"