add(cepgo): import github.com/cloudsigma/cepgo
add(goserial): import github.com/tarm/goserial
feat(datasource/metadata): Add datasource for CloudSigma
Merge pull request #196 from Vladimiroff/cloudsigma

cloudsigma: Add support for CloudSigma datasource
metadata: Refactor common parts out of ec2
digitalocean: Add DigitalOcean metadata service
networkd: Fix bug causing bonding to always be loaded
datasource: Add FetchNetworkConfig

FetchNetworkConfig is currently only used by ConfigDrive to read the
network config file from the disk.
network: Add support for multiple addresses and HW addresses

Logical Interfaces can be assigned a hardware address allowing them
to match on MAC address. The static config method also needs to
support specifying multiple addresses.
digitalocean: Add support for processing network config
test: Refactor interface tests a little