Bumped dependency to Xfce Panel 4.9, and replaced Orientation code
against Mode.
Properly support three modes Horizontal, Vertical, and Deskbar by
respecting the Panel HIG. Fixes also bug 8959, code sets 1px border
width for very small panels, 2px otherwise.
Use pixel fixed width (60px) instead of width_chars for labels, because
in vertical mode the size is incorrect.
Fix 9073, custom colors wasn't working for the progress bars, this has
been fixed while rearranging the code.
Romain B