lib/sysfs: add subsystem and hotplug detection

Signed-off-by: Karel Zak <kzak@redhat.com>
eject: use sysfs API to detect hotplug

Signed-off-by: Karel Zak <kzak@redhat.com>
lsblk: add HOTPLUG column

Signed-off-by: Karel Zak <kzak@redhat.com>
docs: update TODO file

Signed-off-by: Karel Zak <kzak@redhat.com>
lsblk: add SUBSYSTEMS column

 $ lsblk -oNAME,SIZE,TYPE,SUBSYSTEMS /dev/sr0
 NAME  SIZE TYPE SUBSYSTEMS
 sr0   7.8M rom  block:scsi:usb:pci

Signed-off-by: Karel Zak <kzak@redhat.com>
libfdisk: fix cfdisk freespace analyze

The problem is how fdisk_partition_cmp_start() compare numbers, the
function returns result from "a->start - b->start", unfortunately the
numbers are uint64, but function returns "int".

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1170191
Signed-off-by: Karel Zak <kzak@redhat.com>
libfdisk: rename sector_t to fdisk_sector_t

.. just to avoid too generic names for public API.

Signed-off-by: Karel Zak <kzak@redhat.com>
libfdisk: remove 'end' from struct fdisk_partition

This struct member duplicate "start+size".

Signed-off-by: Karel Zak <kzak@redhat.com>
libfdisk: fix bug in cmp_numbers() and partitions sorting

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1170191
Signed-off-by: Karel Zak <kzak@redhat.com>