Update pipe.rb output - Fix LOGSTASH-1860

This adds EBADF to the rescue block as that is what is being thrown when the pipe command gets shutdown (usually due to an error.) Verified that it will restart the pipe and requeue the event that noticed that the pipe had failed and that logstash does not crash due to the pipe command failing.
Fix core-contrib (again) after branch delete.  Keep json filter in core.
die head ist der kopf
Merge pull request #1044 from kurtado/tutorial

die head ist der kopf
version note, attempt at sane headings
Merge pull request #1045 from kurtado/tutorial

LS<->ES version note, attempt at sane headings
Merge pull request #1034 from ronnocol/patch-1

Update pipe.rb output - Fix LOGSTASH-1860
Merge pull request #1035 from untergeek/core-contrib

Bump JRuby & ES versions. Fix core-contrib (again) after branch delete.  Keep json filter in core.