disable lkvs
open method
fix: scsi should no open the SG device using O_DIRECT
remove the blkdev backend
remove the stub ata backend
remove inquiry support

use sg_inq instead
introduce close method
use a private device structure for zbc_fake
add zbc_private.h for private interfaces
Added support for new zone conditio, reporting options and
non-seq bit in the zone information (as per zbc-r01b specs).

Also fixed emulation code for read/write checks (span zone,
 not at write pointer, etc). Also prevent conventional zone
condition and write pointer from being changed by writes.
Merged zbz_need_reset and zbz_non_seq fields in zone information
into a single field zbz_flags.
Updated README to reflect changes in exported API and added comments
on use of native and emulation mode.
Reverted zbz_flags to zbz_need_reset and zbz_non_seq fields
in zone information to stay binary compatible.