removed dead links from example applications

doc/examples.rst

@@ -8,17 +8,9 @@ The repository contains a number of simple examples for building applications
 with different frameworks:
 
 - `A console application <https://github.com/takluyver/pynsist/tree/master/examples/console>`_
-- `A tkinter application <https://github.com/takluyver/pynsist/tree/master/examples/tkinter>`_
-- `A PyQt4 application <https://github.com/takluyver/pynsist/tree/master/examples/pyqt4>`_
 - `A PyQt5 application <https://github.com/takluyver/pynsist/tree/master/examples/pyqt5>`_
-
   - `PyQt5 with QML <https://github.com/takluyver/pynsist/tree/master/examples/pyqt5_qml>`_
   - `PyQt5 with OpenCV <https://github.com/takluyver/pynsist/tree/master/examples/pyqt5_opencv>`_
-
-- `A PyGTK application <https://github.com/takluyver/pynsist/tree/master/examples/pygtk>`_
-
-  - `PyGTK with Numpy and Matplotlib (32 bit, Python 2.7) <https://github.com/takluyver/pynsist/tree/master/examples/pygtk_mpl_numpy>`_
-
 - `A PyGI (or PyGObject) application with Numpy and Matplotlib (64 bit, Python 3.4) <https://github.com/takluyver/pynsist/tree/master/examples/pygi_mpl_numpy>`_
 - `A pygame application <https://github.com/takluyver/pynsist/tree/master/examples/pygame>`_
 - `A pyglet application <https://github.com/takluyver/pynsist/tree/master/examples/pyglet>`_