removing TrayIcon.dll, bug #158608

[Alex Graveley <alex beatniksoftware com>]

Hi,

Just created bug #158608, which removes the use of TrayIcon.dll and its
libtrayicon.so, creating a libtrayiconglue.so in the glue directory.

This is done by making BestTray extend Gtk.Plug, and in the constructor
set the Raw pointer to the return of egg_tray_icon_new, which we call
directly.

This allows the removal of all the cruft in Best/TrayIcon.

Okay to commit?

-Alex