Show main window before ipcReady

It doesn't flicker anymore if we remove this option, and the app feels
no slower.

main/windows/about.js

@@ -31,7 +31,6 @@ function init () {
   // No menu on the About window
   win.setMenu(null)
 
-  // TODO: can this be removed?
   win.webContents.on('did-finish-load', function () {
     win.show()
   })

main/windows/main.js

@@ -36,7 +36,6 @@ function init () {
     icon: getIconPath(), // Window icon (Windows, Linux)
     minWidth: config.WINDOW_MIN_WIDTH,
     minHeight: config.WINDOW_MIN_HEIGHT,
-    show: false, // Hide window until renderer sends 'ipcReady'
     title: config.APP_WINDOW_TITLE,
     titleBarStyle: 'hidden-inset', // Hide title bar (OS X)
     useContentSize: true, // Specify web page size without OS chrome