wip commit for dock layout api
fix a bug with local variable name shadowing
Merge branch 'master' into dock-layout-api
allow none for the primary dock layout node
add traversal methods to the dock layout objects
fix a typo and make node coercion more flexible
make use of the parentDockArea method
update the programmatic layout api
code cleanup of the programmatic layout api
handle the changes to the programmatic layout api
add a method to find the ancestor dock tab widget.
more layout op handlers and code cleanup

This implements the rest of the layout op handlers.
It also refactors a lot of repeated code in contextmanager methods.
add the beginnings of a public styling api
first cut at a style->stylesheet converter
get rid of the temp default stylesheet
add missing style getter. remove debug print.
Move the dock area style to a new module.

This adds a few color schemes on top.
Code cleanup. Formal style interface.
fix docstring typo
temporary updates for testing new styles