begin work on glibs list types
add List, more trait impls on List + SList
remove warning from test file
add notebook layout
add Stack container
add StackSwitcher
add Revealer container
add Overlay container
add Scrollable trait + Layout container
add HeaderBar
add FlowBox + FlowBoxChild
add ActionBar
add ListBox + ListBoxRow
New trait : filechooser
New widgets : filechooserdialog, filefilter
New GLib element : gerror