message: Add "rush:cover" and "rush:test" scripts
diff: "rush:install": "node ./common/rush.js install",
  "rush:build": "node ./common/rush.js rebuild -v",
  "rush:lint": "node ./common/rush.js lint",
  + "rush:cover": "node ./common/rush.js cover",
  + "rush:test": "node ./common/rush.js test",
  "build": "echo use 'rush rebuild'",
  "clean": "rimraf coverage ts-node",
  "lint": "echo use 'rush lint'",
  