fix: NW.js module is not defined fix.

Now the factory assignment for localforage is applied to `global.modules.exports` instead of `modules.exports` if `module` is undefined. `module` is undefined in an NW.js environment (for whatever reason). So now we check for module and we uses global if `module` is undefined. Otherwise we proceed as before. Thank @ashleyhindle for fix. Fixes #77

Author: bradtaniguchi

dist/angular-localForage.js

@@ -14,7 +14,11 @@
  return factory(angular, localforage);
  });
  } else if(typeof exports === 'object' || typeof global === 'object') {
- module.exports = factory(angular, require('localforage')); // Node/Browserify
+ if(typeof module === 'undefined') {
+ global.module.exports = factory(angular, require('localforage')); // NW.js
+ } else {
+ modules.exports = factory(angular, require('localforage')); // Node/Browserify
+ }
  } else {
  return factory(angular, root.localforage); // Browser
  }