[thin_dump] add -o switch
[features] dump/restore is a noop
[features] dump matches original metadata

Currently failing
[thin_dump] Fix regression where mappings for all devices were being listed in every device.
[thin_dump] bug in last bug fix
create_xml_data: fix nr_data_blocks
create_xml_data: fix device and range_mapping
thin_metadata_size,create_xml_data: fix units
thin_metadata_size: drop signe_mapping to =
thin_metadata_size: check for block size > 0
create_xml_data: support --size-variation and check for block size > 0
create_xml_data: remove space in dev_id ouput
create_xml_data: adjust filed order to thin_dumo format; fix nr_data_blocks
create_xml_data: adjust to thinp_xml output
create_xml_data: fiddling
create_xml_data: simplify to mappings; drop all units
Merge branch 'Work_1' of github.com:lvmguy/thin-provisioning-tools into Work_1
create_xml_data: fix mapping variation check