replace underscore with our own

we only need like 5 simple functions

src/platform.js

@@ -37,7 +37,7 @@ const apps = require('./apps.js'),
     updater = require('./updater.js'),
     users = require('./users.js'),
     volumes = require('./volumes.js'),
-    _ = require('underscore');
+    _ = require('./underscore.js');
 
 let gStatusMessage = 'Initializing';