Rename window.env to window.config

Also normalize to camelCase for configs.

// FREEBIE

preload.js

@@ -5,11 +5,11 @@
 
 console.log('preload');
 
-window.env = {};
+window.config = {};
 window.location.search.substring(1).split('&').forEach(function(variable) {
   var pair = variable.split('=');
-  env[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
+  config[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
 });
 
 const ipc = require('electron').ipcRenderer
-window.env.locale_json = ipc.sendSync('locale-data');
+window.config.locale_json = ipc.sendSync('locale-data');