When a PV VM is booting via pygrub (or other bootloader) we need to provide a list of devices to boot from

We now parse the disk information before creating the VM, so we can
add the boot device information.
Merge branch 'master' of git://github.com/djs55/xenops-cli
Kernel and ramdisk names need to be converted to absolute paths for xenopsd

The CLI has a current working directory which can be used to resolve relative
paths in VM config files.
Add CLI command "console <vm>"
Add 'start <vm> --console' to start and automatically attach to the console
In xl-style config files "builder=generic" means PV while "builder=hvm" means HVM

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge branch 'master' of github.com:djs55/xenops-cli
Add 'xenops-cli create' which import xl-style VM metadata and immediately starts the VM.