Set version to 1.3.1
Noticed and fixed accidental hiding of register_window method in Gtk.Widget
House keeping
Added more official licensing, fixed author list.
Started plugin system development
Further progress to adding plugins.
Further plugin component development.
Further plugin work
Further plugin work.
Plugin components system complete.
Added plugin component definition for AltAND.
C code updated.
Updated resources tar
Tidy up of autotools file.
Fixed plugin library finding and custom and plugin set last buttons.
Updated C Code.
Autotools update.
Fixed plugin reference saving in project files.
Clean up of autotools files.