Add buildpacks to DEA (not finished).

- Haven't merged Buildpack specs into global specs
- Haven't used the new buildpack code in DEA, still using vcap-staging

Change-Id: I29ff41bc0ffc7b3a8e691653270571e8b91a4490
Moved the buildspec to the global spec

Change-Id: Iafe93cf4a068ac728c74209d6fcb2d4d81b90fdf
Stopped using vcap staging instead use local buildpack

Change-Id: Ieb94416d855b78d51b1ba45f002e7b47405be4ec
simplify run staging script since we only support buildpacks
stop mounting shared gems dir since staging only uses stdlib
Don't require buildpack code in staging task
Simplify buildpack spec support
Fix some file paths
Add chef recipe for installing ruby in warden image
Merge branch 'merge_vcap_staging'

Conflicts:
	Gemfile.lock
Mark logplex integration test pending for now
Merge branch 'master' of github.com:cloudfoundry/dea_ng