Use the same icon set in x-gtk-stock-map.
* COMPILE (riece-icons): Re-order filenames. * Makefile.am (EXTRA_DIST): Add new toolbar icons. * riece-command-change-layout.xpm: * riece-command-configure-windows.xpm: * riece-command-join.xpm: * riece-command-part.xpm: * riece-command-quit.xpm: New toolbar icons.
* riece-command-previous-channel.xpm: New file. * riece-command-next-channel.xpm: New file. * COMPILE (riece-icons): New variable. (riece-install-icons): New function. (riece-install): Install icons. (riece-install-package): Ditto.