Rework layouts: Layout is now normal Container which places its children upon resize event.
Drop TopWindow, top is now any subclass of Container.
Add floater concept: floaters are widgets drawn over normal widgets, not clipped by parent.
Add HScrollbar and Scrollbar abstract base class.
TreeView
========
.. toctree::
:maxdepth: 3
:titlesonly:
.. automodule:: tuikit.treeview
:members:
:show-inheritance:
Path
----
The path may be string or list. Components are names or indexes.
String path uses slash char as separator, names as components.
Examples:
* '/'
* '/a/b/c'
* ['a', 'b', 'c']
* [0, 3, 1]