Improve webpack 2 usage/compat

Fixes #71

Context: webpack/webpack#4742

Author: bfred-it

package.json

@@ -31,8 +31,6 @@
     "preprocessors"
   ],
   "main": "dist/ofi.common-js.js",
-  "module": "dist/ofi.es-modules.js",
-  "jsnext:main": "dist/ofi.es-modules.js",
   "scripts": {
     "build:js": "bfred-npm-bundler ofi objectFitImages",
     "build": "npm-run-all --silent jsfix build:*",