This patch changes the decorator to always apply stacking-order changes
immediately instead of deferring the re-stacking of the nitpicker views
to the next call of 'update_nitpicker_views'. The deferred application
did not always work when more then one windows changed their stacking
position at once because the cached '_neighbor' values interfered with
each other.
The eager re-stacking should not have negative effects on the user
experience because, in contrast to re-positioning, re-stacking a rare
operation.
This change makes it possible to reuse the generic window decorator
classes in include/decorator/ for decorators of a different structure.
E.g., instead of painting decorations on a single nitpicker session,
each window may paint its decorations into additional window-specific
nitpicker sessions.
This patch improves the decorator in two ways. First, it enables the
assignment of window colors depending on the window labels. This
configuration can be changed dynamically. Second, it adds the handling
of window controls for closing, maximizing, minimizing windows.
Issue #1689Fixes#1688