When the focused window was closed without a new window receiving focus, the
closed window was not removed from the history database, making for example
"nextMatch History (return True)" misbehave. This patch fixes this.
This patch replaces the use of Seq.filter and Seq.breakl with two
functions flt and brkl that do the same. This is necessary to
keep compatibility with containers < 0.3.0.0 because Seq.filter and
Seq.breakl were introduced only in containers 0.3.0.0.
This module adds two related facilities. The first one allows cycling through
the windows in a window group. A group is defined as the set of windows for
which a given Boolean Query returns True. The second one keeps track of the
history of focused windows and allows returning to the most recently focused
window in a given window group before the currently focused window.
