pass disk identifier as string to agent in settings.json

 * This makes disk identifiers a consistent type with AWS and OpenStack
 * This also allows for consistent json unmarshalling in the Go agent

Signed-off-by: Michael Maximilien <maxim@us.ibm.com>
introduce cdrom package to handle waiting for cdrom ready

Signed-off-by: Rob Day-Reynolds <rdayreynolds@pivotallabs.com>
move platform test setup into BeforeEach and inline test helpers

Signed-off-by: Rob Day-Reynolds <rdayreynolds@pivotallabs.com>
implement system specific cdrom interface
introducting cdutil for getting files from a cdrom
wiring in cdutil into platform for GetFileContentsFromCDROM
combine ubunt and centos disk manager to linuxDiskManager
inject compressor, copier, and vitals service into centos and ubuntu platforms
initial extraction of dependencies from centos and ubuntu into linux platform
move common platform functionality into linux platform
extract centos and ubuntu network configuration to net package

 * inject net manager into linux platform
 * replace ubuntu and centos platforms with linux platform
change assertions to gomega in vsphere infrastructure tests

Signed-off-by: Michael Maximilien <maxim@us.ibm.com>
fix interface lookup by mac address

MAC addresses were being obtained from /sys/class/net/*/address.
These files contain newlines that need to be trimmed off.

Signed-off-by: Michael Maximilien <maxim@us.ibm.com>