Update version of Play used from 2.10 to 2.15

There are security vulnerabilities in 2.10 - http://www.playframework.com/security/vulnerability/20130920-XmlExternalEntity and http://www.playframework.com/security/vulnerability/20130806-SessionInjection.

The dataload process has been tested successfully with 2.15 and elastic search works.  It requires further testing before committing.