add convenient script

Author: Almenon

package.json

@@ -8,7 +8,8 @@
   "scripts": {
     "test": "tsc -p ./ && mocha -r ts-node/register",
     "appveyorTest": "tsc -p ./ && nyc mocha --reporter mocha-appveyor-reporter test/*.js",
-    "compile": "tsc -watch -p ./"
+    "compile": "tsc -watch -p ./",
+    "compileOnce": "tsc -p ./"
   },
   "devDependencies": {
     "@types/mocha": "^8.2.1",