add the DockTab class
disable automatic tab creation in the dock bar
add first cut at DockItem class
variable naming, code ordering
add the first cut of a DockPanel
code ordering
fix typos
only export DockArea and DockItem in the public API
wip commit
rename dockbar -> tabbar within a DockPanel
unset the current tab before tearing it off
move push/pop cursor to tab mover
add a fixme comment
wip