refresh navbar starstuff when I've not starred it

for #245
unstar notebook on removing it

was just removing it from interests, resulting in inconsistent state

fixes #245
don't pass rcs engine as list argument
do set star state and star sub when unstarring in the treeview
when setting star button state, set the star state (!)
add continuation to star_notebook

so that That Case where we delete the current notebook and create a new
notebook, doesn't stomp on the unstar in progress