File Storage Engine Choice

[millmanw]

Adding the configuration and engine integration to allow the Zulia administration to choose to store media files in S3 rather than GridFS

[mdavis95]

Sample config

{
	"dataPath":"/data/zulia",
	"cluster":true,
	"clusterStorageEngine":"s3",
	"s3": {
		"s3BucketName":"someBucket",
		"region":"someRegion"
	}
}