Locksmith is a simple app that will replace text as you type. It is comprised of a system preferences pane and a small helper application to prevent any unsightly icons in your dock or menubar.
Clone the repo and open Locksmith.xcodeproj in the latest Xcode 6 beta. There will be two targets, the preferences pane Locksmith (Objective-C) and the helper application LocksmithHelper (Swift). Building the preferences will also build and embed the helper application. When you build the preferences pane it will be installed into ~/Library/PreferencePanes.
.
├── Locksmith.xcodeproj The Locksmith Xcode project
├── Locksmith Preferences pane
├── LocksmithHelper Helper application
└── LocksmithHelperTests Helper application tests (someday...)