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
Change [A|a] by [Aa], etc.
Try more times to fetch from rubygems.org

Of the last 14 build failures, 6 of them were because of bad_record_mac.
Hopefully retrying more will work around this.
fix handling of more than 2 repetitions of same mail header
bluecloth is needed to build the docs
json_lines codec documentation is special since it isn't used with the file input.
Also fixed formatting issues with the config examples in the synopsis section.
actually encode to UTF-8 when input charset is non UTF-8 + basic specs
explicit return for explicit explicitness
    Fix bug LOGSTASH-1225 "Cannot Clone Fixnum"

    The clone {} filter will throw an exception if any of the values in the
    event map are numbers. Problem is that numbers are not clonable.

    This is a single-line fix that wraps the .clone call in a try block and
    does a simple set-by-value if the clone raises an exception.

    Included under spec/filters/clone.rb is a test case that fails without
    the change in lib/logstash/event.rb and passes with the fix applied.
Fix event::overwrite to copy timestamp properly
updates as per code review
Merge pull request #1161 from rtkmhart/master

Fix event::overwrite to copy timestamp properly
Actually clear GEM_PATH

This helps ensure we provide only our own gem directory for rubygems.

Helps improve LOGSTASH-1918. Before this patch, my local ruby install
was accidentally providing 'rack' so I never noticed this problem.
Add 'rack' gem back in

This is required for 'logstash web' to serve Kibana and was
removed accidentally.

This fixes LOGSTASH-1918