tree.reactivate(false) sets fancytree-treefocus (without setting focus)

[mar10]

• tree.reactivate(false) sets fancytree-treefocus class to container (without setting keyboard focus)
• tree.reactivate(true) sets fancytree-treefocus to container and fancytree-focus to node, but without setting keyboard focus

[mar10]

Reopened, because the current change caused a regression: #570