After looking at the GtkSourceView headers it seems correct to
do the following in the "Syntax Colors" in Prefs:
1)
gtk_source_languages_manager_new
gtk_source_languages_manager_get_available_languages
...which gives us a GSList which we can stuff into a TreeView or
a List. And when the user clicks on one of those:
2)
GSList* gtk_source_language_get_tags
...and for each one of those display them (maybe again in a TreeView)
with their corresponding colors where the user can change them.
We must save the user's color settings in his home dir then.
Do you agree on this?