docs: Update Debian Wheezy installation guide for 0.16
cyclades: Return 403 instead of 401 in subnets

Return 403 (Forbidden) instead of 401 (Unauthorized) in certain subnet
actions.
pithos: Add test

Add test for listing only objects that do not have specific metadata.
pithos: Fix issue with JSON serialization

Method 'get_account_headers' should return list
(JSON serializable) instead of set.

Closes grnet/synnefo#194
ui: Correct initialization of missing flavor object

include missing cpu/disk_template parameter while handling the response of
explicit calls made in order to retrieve details of a flavor id which is not
listed witin the initially retrieved flavors data.

Closes grnet/synnefo#193
astakos: Use webproject URLs as urlconf in reverse

Use "synnefo.webproject.urls" as urlconf in the reverse() calls of
`im/models.py/` and `im/user_utils.py`.

The reason why we explicitly use the webproject URLs is because Admin,
which imports functions from Astakos, may use a different ROOT_URLCONF
in order to disable the Astakos/Cyclades API. Therefore, If a user
needed to resend a verification mail from the Admin Dashboard, the
reverse would fail.

Closes grnet/synnefo#183
pithos: Several PEP8 and test fixes
pithos: Apply metadata/group limits for the resources

This commit sets a maximum metadata number per Pithos
resource as well as a maximum group number per account
and a maximum allowed number of group members.

More specifically:
* Introduces two new settings for Pithos:
* the maximum number of metadata each resource
  (account/container/object) can have,
  the maximum number of groups each account can have
  and the maximum number of members each group can have.
* Adds checks to enforce the above limits.
* Introduces the LimitExceeded exception raised by the backend
* when these limits are infringed.
* Refactors the backend implementation of the group/metadata
  update in order to reduce interaction with the database.

The affected backend methods are:
* update_account_meta
* update_container_meta
* update_object_meta
* register_object_map
* copy_object
* move_object
* update_object_hashmap
* update_account_groups

Applications, other than Pithos+, that use the Pithos backend
should put a special care on handling these situations.
plankton: Handle limit exceptions.

Pithos backend enforces limits on the number of the resource metadata.
If these limits are exceeded a LimitExceeded exception is raised.
Plankton should catch these exceptions and fail with BADREQUEST (400).
docs: Update storage API