Plugin now also adds a menu item in the file menu to open the Browser

https://app.asana.com/0/15066612015532/15028213105404

If Browser doesn't exist att Xcode launch, it sends a log to the console (not the xcode console). If it existed at Xcode launch but not when the menu item was chosen, it displays a dialog.

The old plugin only added RLMObject templates, now we have a place to actually run code, not limited to adding menu items.

Plugins break easily but this should work in both Xcode 5 and 6.
Why are you passing `NSWorkspaceLaunchConfigurationArguments`? How does the browser handle this?