Validate VMX file

[Camilo Aguilar]

We need to discover what makes a VMX valid or not. So far we know:

• A VMX missing its vmdk disks is invalid. We need to check SCSI, SATA and IDE arrays, if no disks is found, report an error to the user.
• memsize has to be multiple of 4
• Link state propagation is only permitted for bridged networks
• Static MAC addresses have to start with VMware officially assigned prefix: 00:50:56