resolves error thrown when mac_id is missing from RESTful call to boot endpoint
Merge pull request #170 from tjmcs/tb/fix-error-when-missing-boot-mac-id

Fixes #169 (Error thrown when `mac_id` is not included in boot call)
Copied and modified the ESXi 5 model including an optional parameter for vSAN uuid, modified kickstart.erb for vSAN modifications