'src/generator.ml' is no more.  Instead the generator is logically
split up over many different source files.

Read generator/README for help and tips.

We compile the generator down to bytecode, not native code.  This
means it will run more slowly, but is done for maximum portability.

This commit combines the previously separate "inspector_generator.ml"
program which generated bindings for virt-inspector.

Having two separate programs caused no end of troubles for developers,
so we now combine them into a single program.

NOTE: OCaml xml-light is now *required* in order to rebuild the
generated code.

This commit introduces a generic partition creation interface
which should be future-proof and extensible, and partially
replaces the old sfdisk-based interface.

The implementation is based on parted but is hopefully not too
dependent on the particulars of parted.

The following new calls are introduced:

  guestfs_part_init:
    Initialize a disk with a partition table.  Unlike the sfdisk-
    based interface, we also support GPT and other partition
    types, which is essential to scale to devices larger than 2TB.

  guestfs_part_add: Add a partition to an existing disk.

  guestfs_part_disk:
    Convenience function which combines part_init & part_add,
    creating a single partition that covers the whole disk.

  guestfs_part_set_bootable:
  guestfs_part_set_name:
    Set various aspects of existing partitions.

  guestfs_part_list:
    List partitions on a device.  This returns a programming-friendly
    list of partition structs (in contrast to sfdisk-l which cannot
    be parsed).

  guestfs_part_get_parttype:
    Return the partition table type, eg. "msdos" or "gpt".

The following calls are planned, but not added currently:

  guestfs_part_get_bootable
  guestfs_part_get_name
  guestfs_part_set_type
  guestfs_part_get_type

(Just whitespace and comment changes, and small restructuring
of the code).

We have to include this generated file because it is part of
the build system, thus required to exist before the generator
runs.