add drain script for elasticsearch /issue #51
settle on curl and subshells /issue #51
additional drain testing and cleanup /issue #51
subshells over backticks /issue #51
Adjust logstash.filters configuration and location of default, embedded filters.
By default, embedded filters are no longer included if you specify your own
filters. See example/warden.yml for a way to continue doing this.

 * issue logsearch/logsearch-boshrelease#58
Minor tweaks after additional testing of drain script.

 * issue #51
Make logstash filters configuration an embedded spec value. This is most useful
when using manifests with ERB templates (see examples/bosh-lite.yml)

Issue #60
Merge branch 'elasticsearch-drain' into develop

Conflicts:
	examples/bosh-lite.yml
Merge branch 'refactor-filters' into develop
Make filter configuration more dynamic (note the path is relative to the working directory).

Issue #60