Cleanup logging flag for agent
ES 1.3.4 has been released and contains only minor bugfixes. Setting as default version
Check for logstash basedir and error nicely

Fixes https://github.com/rackspace-cookbooks/elkstack/issues/64
Fix rubocop line too long
Version bump
Adds support for backups via snapshot API

Fixes https://github.com/rackspace-cookbooks/elkstack/pull/45.