Fix not specifying file name with test in package.json (#289)

This makes it possible to test each file with `npm test FILE_NAME`.

package.json

@@ -7,7 +7,7 @@
  "test": "test"
  },
  "scripts": {
- "test": "mocha test/*.js"
+ "test": "mocha"
  },
  "bin": {
  "node-lambda": "./bin/node-lambda"