Documentation updates, logging, non-breaking variable rearranging
Bump elasticsearch to 1.3.3
Reduce agent memory, fix typo, rearrange agent attributes
Fix upstream logstash, rearrange agent attributes

- Fix an upstream logstash cookbook issue, contribute it back upstream ([#360](https://github.com/lusis/chef-logstash/pull/360)). Once that is merged, we can go back to upstream.
- Move agent attributes out more, to be their own explicit settings.
Merge pull request #53 from martinb3/master

Minor fixes for elkstack, bump ES to 1.3.3