Merge branch 'next'

* next: (26 commits)
  Some documentation fixes and enhancments.
  Improve INSTALL documentation.
  README: Update copyright notice.
  README: improve phrasing.
  Change handling of warnings.
  Improve output padding.
  Check for invalid newsgroup names.
  Add some basic validation to config parser.
  Create better newsgroup lists for SQL clause.
  Fix config path detection for install.pl.
  Get empty 'virtual' hierarchies working.
  Add some TODO entries.
  Add database creation to installer.
  Handle undefined previous version when installing.
  Refactor database initialisation in feedlog.pl.
  Add empty 'virtual' .ALL hierarchies as needed.
  Change interpretation of --checkgroups to template
  Be more fault-tolerant when reading checkgroups.
  Remove call to &Bleat where not appropriate.
  Allow more characters in TLH definitions.
  ...