Update canary breeder and canary assets

- Breeder pushes long-running canary with 128M of memory
- CLI command defaults to 'cf' instead of 'gcf'
- Reduce memory of zero-downtime canaries to 128M
- Reduce memory of instances canaries to 128M
- Reduce memory of network canary to 128M
- Reduce memory of disk canary to 512M
- Convert go canaries to Godeps
- Remove unneeded app manifests from assets
- Clean up RSpec deprecation warnings