modified build script and version bump

package.json

@@ -1,13 +1,14 @@
 {
   "name": "docx",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Generate .docx documents with JavaScript (formerly Office-Clippy)",
   "main": "build/index.js",
   "scripts": {
     "pretest": "rimraf ./build-tests && tsc -p ts/test-tsconfig.json",
     "test": "mocha ./build-tests --recursive",
-    "prepublishOnly": "tsc -p ts",
+    "prepublishOnly": "npm run build",
-    "lint": "tslint --project ./ts"
+    "lint": "tslint --project ./ts",
+    "build": "rimraf ./build && tsc -p ts"
   },
   "files": [
     "ts",