Use files field in package.json

Author: Michael Sargent

.npmignore

@@ -26,6 +26,11 @@
  "engines": {
  "node": ">= 4"
  },
+ "files": [
+ "dist",
+ "es",
+ "lib"
+ ],
  "dependencies": {
  "history": "^4.6.1",
  "query-string": "^4.3.4"