See #109: added gui state writer/reader to write/read separate gui state
files as written in my comment
Fixes #109:
added updateGUI method in MainFrame to centrally update GUI components
after new GUIConf was loaded at runtime;
added updateGUI methods in relevant classes (context, lattice,
dependencies);
added further elements to GUI state and fixed the ones that already
exist but did not work;
GUI state is now saved when opening new context;
improved javadoc in GUIConf;
fixed typo in GUIConf