#37 Update the GUI to not use deprecated API

[Errol van de l'Isle]

Remove the last of the optional GTK 1 code.

Replace the deprecated GTK+ 2 API access. For example change the GtkCLists to GtkTreeView, GtkFileSelection to GtkFileChooser, do drawing with Cairo, and many more.

This will be a long term project and at times will require that the minimum GTK 2 requirement is increased. This will do minimal changes to the look and feel of the GUI for gpsim.

There is already one module in extras that requires gpsim to be compiled with at least GTK+ v2.8 to work.

[Errol van de l'Isle]

A quick update on the GUI for Gpsim.

The minimum GTK+ requirement for the GUI is now v2.24. The Microsoft Windows binary has been built with 2.24 for a long time and 2.24 has been around for many years so should not be a problem for anyone.

Gpsim can now be built with -DGSEAL_ENABLE. So access to widgets have to be done via functions and not directly accessing the internal variables.

I and currently working through the code so that it would be possible to compile with -DGTK_DISABLE_DEPRECATED=1. So far many deprecated widgets have been replaced or dead code containing these removed. There is still much more to do.

The next step afterwards would be to replace the calls to the deprecated GDK functions.

Errol.

[Errol van de l'Isle]

Gpsim can now be built with -DGTK_DISABLE_DEPRECATED=1 as well as -DGSEAL_ENABLE. This is a good indication that any deprecated calls to GTK have now been replaced or removed.

The next step is to replaced the deprecated GDK calls which would include converting some of the code to use Cairo.