Fixed: QueueView hides queues that do not have at least one unlocked ticket (bug#8244).
Squashed commit of the following:

commit b5a7591884be5f5ffd8f33429c5e4665de84af10
Author: Dietmar Berg <dietmar.berg@thalesgroup.com>
Date:   Wed Jan 29 11:46:40 2014 +0100

    Bugfix#8244 QueueView hides queues w/o unlocked tickets

    Currently QueueView only allows to navigate to queues which have at least one unlocked ticket.
    Once the queue becomes visible, it is well possible to switch between filters that show either
    All open or just Unlocked tickets in that queue.

    Encouraged by very positive feedback in the bugzilla ticket http://bugs.otrs.org/show_bug.cgi?id=8244#c4,
    this PR modifies the behaviour as follows:

    All readable queues have both non-closed and unlocked tickets enumerated. The results are
    presented in the "Queue Bar" in the same order as the filters. This overview continues to
    be generated through the the IndexAccelerator backends which have been modified accordingly.
    Their queries now count tickets grouped by lock, and the filtering/consolidation is done in
    code, so they can return a complementary 'Total' field in addition to the existing 'Count'.

    A bug that produced incorrect sum of the number of tickets in nested queues has also been fixed.
Improved FormatTimeString implementation, added unit tests.