[20160720211125] Existing VPCs, Fluentd, and More

Existing VPCs

You can now create a Rack in an existing VPC during convox install (#837) [@ddollar]

$ convox install --existing-vpc vpc-12345678 --existing-subnets=10.0.1.0/24,10.0.2.0/24,10.0.3.0/24

Fluentd

You can now stream your logs to fluentd by adding a service. (#893) [@adamenger]

$ convox services create fluentd --url=tcp://fluentd-collector.example.com:24224

General Enhancements