touch up statsd output
explain defaults
touch up
fix handling of more than 2 repetitions of same mail header
Merge branch 'doc/output/statsd' of https://github.com/kurtado/logstash into kurtado-doc/output/statsd

Conflicts:
	lib/logstash/outputs/statsd.rb
Merge branch 'imap_header_repetition' of https://github.com/colinsurprenant/logstash into colinsurprenant-imap_header_repetition

Conflicts:
	lib/logstash/inputs/imap.rb
Merge remote-tracking branch 'upstream/master'