TGUI 0.7 is no longer supported, use a newer TGUI version instead.
Tip: The sfml example comes with a resourcePath() function which you have to put before the paths to load resources. You can use tgui::setResourcePath(resourcePath()) at the beginning of your program so that everything tgui loads starts with that folder.
In order to install the library, just copy the framework to the /Library/Frameworks folder.