Log Message:
Updated mrtg to 2.9.25

* die gracefully when LANG is set to UTF-8 and give advice (RedHat 8)
* updated squid monitoring example
* Fixed indexmaker which got truncated during the last release process
* cosmetic tweaks for layout
* Use Snmp Session 0.93 with option avoid_negative_request_ids enabled
* Supress Posix Locales in the locale module ... people who have LANG
  set to UTF-8 report very strange errors otherwhise.
* skip all queries to a host for one round when 1 query has returned undef.
* skip all trailing space in keys when matching interface by Name,
  Description, Anything
* remove <br> before <hr> near pagetop
* make Includes search in directory of main config files as well as in
  current directory
* addhead option for indexmaker
* fix for uptime for squid and other non standard devices
* indexmaker: improve handling of urls given with --rrdviewer
* improved chinese translation