add compile prepare script

Author: cbartondock

package.json

@@ -41,7 +41,8 @@
     "test": "yarn compile && TS_NODE_PROJECT=test/tsconfig.json ava",
     "lint": "tslint -c tslint.json 'src/**/*.ts'",
     "docs": "typedoc src/index.ts",
-    "prepublish": "yarn lint && yarn test && yarn docs"
+    "prepublish": "yarn lint && yarn test && yarn docs",
+    "prepare": "yarn compile"
   },
   "ava": {
     "files": [