Add borders to toolbars etc.
Fix a potential memory leak.
Be explicit about void argument lists.
Allow docked applications to be non-square.

As mentioned in issue #95, before this commit, applications docked in
the tray would be scaled to the largest square size that would fit on the
tray.  Now applications can be wide for horizontal trays and tall for
vertical trays.
Remove debug print.
Fix a size issue with empty docks.
Fix tray support for multiple monitors (issue #96, patch from @jdoe0154).