Use Elasticsearch 0.90.13
Add memcached restart after API deployment
Fix missing hosts file entry for development

In development, running VMs, if a request is made to the QA app,
it calls the api with the same hostname as the QA app.  If this is
requested on "local.dp.la" then the internal request back to itself
will fail if that hostname is not in /etc/hosts on the server.
Merge pull request #10 from dpla/elasticsearch-0.90.13

Use Elasticsearch 0.90.13
Add staging files
Add api nodes to postgres db's allowed hosts

This omission became apparent after trying to put the PostgreSQL
database on a server of its own.
Add mail role to common configuration
Add ingestion tasks
Add "level" variable to staging_all.yml

Necessary because of recent change to /etc/hosts task in "common"
role.