FR: alias.cutoff to remove clutter from alias items.

[chrisgrieser]

Various menu bar items add a leading icon, which cannot be removed from the app itself. One example is meeting bar, which always adds an icon.

Having a property alias.cutoff would be useful to remove such clutter from the alias, e.g. alias.cufoff.left=30 to remove the leftmost 30 pixel from the alias item. In the case of meetingbar, this would remove the icon and only leave the "upcoming meeting" information.