Log Message:
Updated mrtg to 2.10.13

* fixed undef data problem with forks
* add --icondir option to indexmaker
* faild rrdtune should not kill mrtg complaining is enough.
* fixed manpages first lines to include mrtg as well
* It's community not comunity.
* 16-Bit SNMP Session ID support for cfgmaker and SNMP_Session
* renamed all doc pages to mrtg-* except the manpages for cfgmaker and
  indexmaker
* added MaxAge option setting which will prevent mrtg from touching old
  logfiles, potentially caused by setting the clock to a wrong date.
* fixed a number of && vs and and || vs or problems in the mrtg script and
  library