Changed the MongoMetadataConfiguration to get the configered map of roles
Merge pull request #18 from luan-cestari/metadata_roles_lightblue-rest-issue-1

Metadata roles lightblue rest issue 1
Incorporate MetadataListener
Implement metadata listeners, verify/add _id field, verify/add _id index
Merge remote branch 'origin/metadata-crud-hooks' into metadata-crud-hooks