[collectd] GaugeInc and GaugeAdd DSTypes for tail plugin

[Andre Ferraz]

Hi,
    we did a small patch for tail plugin to include new dstypes for it: GaugeInc and GaugeAdd to get the raw number of ocurrences of the match or the sum of the occures of the same match. On README i saw that the place for new patches is this mailing but
on github there is a lot of pull requests, I dont know if you guys are using github officially for this task, but in case I sent a pull request https://github.com/collectd/collectd/pull/673 , 

Hope That Helps

Regards,