0.9.0

• Add 'failure diagnostic' screen.
  (Closes Debian Bug#646902 by Markus Raab)
• Document ErrPattern statement in apt-dater.conf.
  (Closes SF Bug by Herman van Rink)
• Remove depreciated Tcl_Interp access (required for Tcl8.6+).
• Include config.h before using HAVE_LOCALE_H (provided by Patrick Matthäi).
• New feature: cluster support (README.clusters)
• Sync to apt-dater-host 0.9.0-adp0.6:
  • cluster support
  • depend on ImVirt.pm on Debian