Creates a bootable disk image from a Rust kernel

USAGE:
    cargo bootimage [BUILD_OPTS]        Create a bootable disk image

    (for other forms of usage see `bootimage --help`)

BUILD_OPTS:
    Any options are directly passed to `cargo build` (see
    `cargo build --help` for possible options). After building, a bootloader
    is downloaded and built, and then combined with the kernel into a bootable
    disk image.

