Fixed 'device tree', 'device depends' and 'device provides' with logical partitions.

Before:
$ device depends /dev/sda5

DeviceID                                                 Name      ElementName
/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-4 /dev/sda4 sda4

$ device tree
/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0            /dev/sda   sda         1024M MS-DOS partition table
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part1    /dev/sda1  sda1        94M   ext4
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part2    /dev/sda2  sda2        95M   Unknown
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part3    /dev/sda3  sda3        94M   Unknown
└─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part4    /dev/sda4  sda4        1024  Unknown
  ├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part5  /dev/sda5  sda5        93M   Unknown
  ├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part6  /dev/sda6  sda6        95M   Unknown
  └─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part7  /dev/sda7  sda7        94M   Unknown


After:
$ device depends /dev/sda5

DeviceID                                                 Name     ElementName
/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0 /dev/sda sda

$ device tree
/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0          /dev/sda   sda         1024M MS-DOS partition table
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part1  /dev/sda1  sda1        94M   ext4
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part2  /dev/sda2  sda2        95M   Unknown
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part3  /dev/sda3  sda3        94M   Unknown
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part4  /dev/sda4  sda4        1024  Unknown
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part5  /dev/sda5  sda5        93M   Unknown
├─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part6  /dev/sda6  sda6        95M   Unknown
└─/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-part7  /dev/sda7  sda7        94M   Unknown
Rename 'lmi devices' to 'lmi storage'
Skip CIM_Memory devices, they don't represent storage.

DMTF defines CIM_Memory as subclass of CIM_StorageExtent, but we should not
show it as storage device.
Merge pull request #18 from jsafrane/devel/rename-devices

Rename 'devices' to 'storage' and other minor fixes.