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- validate image metadata format
- read metadata from file
- merge file-loaded metadata with runtimes
- store metadata file on pithos, check existance, overwrite with -f
- raise helpful error messages when there fail

Refs: #3797

- Ensure uniform image meta output
- Easy to apply the correct meta format

Refs: #3797

Refs: #3732

Refs: #3732

Refs: #3780

Log of changes:
- Properties are stored in a remote file on Pithos+
- File name is <image-file>.meta
- Feature can be switched off with --no-property-file-upload
- If remote property file exists, registration is aborted
- If remote property file exists, force with -f, --fforce-upload-property-file
- Location is given as container:path
- User id can be aquired internaly with an astakos call

Refs: #3769, #3778

- Add image.add_member missing content-length header
- Rename image-[add|del]member commands to members-[add|delete]
- Remove update option from image-register
- In image-compute split properties to properties-list and properties-get
- Add optional output to methods
 * image: unregister, members add/delete/set
 * image compute: delete, properties delete
- Transliterate methods to list-get-set-delete command groups:
 * image: members, member
 * image compute: properties

Refs :#3756 #3732

Apply the feature wherever is applicable
Generalize the feature by moving the corresponding code to _command_init

Refs: #3756 #3732

 - Add optional output for file methods: mkdir, touch, create, move, create,
    copy, move, append, delete, purge, info, meta, upload
 - Transliterate permissions and metadata methods to apear as get/set/delete
    command subgroups
    e.g. kamaki file metadata set ...
    instead of
    kamaki file setmeta
- Add method create_container to pithos client, add unit and functional tests

Also, kamaki.clients.pithos.copy/move_object returns response headers

Refs: #3756 #3732

Refs: #3756 #3732

In kamaki.clients
-------------------
- storage.create_directory returns response headers
- implement pithos.create_container

In kamaki.cli.pithos
-------------------
- add flag --with_output for optional output
- add (-j, --json) flag for optional json-formated output
- apply these changes to file_mkdir, file_touch, file_create

Refs: #3608

The download_to_string method downloads a remote object from pithos into a
string, which is then returned.

Also, implemented unit and functional tests. Changelog is updated

Refs: #3608

 Also disallow moving deleted objects by version The later was implemented by
accident, due to the symetry between move and copy

Refs: #3737

Refs: #3739

Refs: #3736

Refs: #3735

Refs: #3707

Refs: #3730

Refs: #3656

This caused warnings about preset variables

Devflow is a GRNET system for handling versions and packaging the verious
GRNET.gr Synnefo software piecies

1. Get rid of OrderedDict dependency (for python <= 2.6)
2. Minor fixes