Add NaN handling config options
input/collectd: Implement handling of NaN values
Add tests for the collectd NaN handeling
input/collectd: Better tagging on NaN

  * Don't overwrite existing tags
  * Allow the user to config the tag to add when a NaN is found
touch up statsd output
explain defaults
touch up
fix handling of more than 2 repetitions of same mail header
shift specs selection from Makefile to leverage rspecs tags
fix timing issue and cleaups
tag :performance for exclusion
tag :redis for exclusion
tag :elasticsearch for exclusion
tag :broken for exclusion
tag :socket for exclusion
PRQ-144: Fix the TCP input so it passes unit tests and does not drop messages under load.
Fieldreference replacement
Merge branch 'specs' into utf8fields
proper utf8 support in plugins which assigned non utf8 event field values
main message codec support and headers transcoding