cyclades: Link serial to resource in handler

Move code that attaches a newly created serial from issue_commission
to handle_resource_commission; the latter is responsible to clean up
previous serials and thus to attach the new one.
cyclades: Accept serial before actually building vm

Since the vm is written in the DB, we accept the corresponding serial
before sending the build job to the backend. This is to avoid
rejecting the serial when the job fails, as is the case with other
kind of actions.
cyclades: Don't reuse a resource object after transaction ends

Accept/reject a serial without touching the respective resource when
we have explicitly committed or rolled back a transaction, because
that would risk overwriting a resource locked in another transaction.
cyclades: Mark vm build serial to accept in advance

When creating a vm, mark the serial as acceptable along with
committing the vm to the db. This makes sure the commission will be
eventually accepted, no matter what fails in the next steps.
snf_django: Remove Help column from filter listing

Rely on a better Description rather than the extra Help column.
astakos: Improve description of AstakosUser fields

These end up as filter descriptions in `user-list --list-filters'.
cyclades: Validate VM metadata on create/update

* Check for VM max metadata items when updating/creating a single item.
* Check the length of metadata items when updating metadata items.
astakos: Fix a unicode bug in user-add

Fix a unicode bug in snf-manage user-add when the username contained
non-ascii characters.
astakos: Add checks for quota limits

Check that total (project) quota limit is no less than member limit;
and that both limits are not negative.
pithos: Recover from DB integrity errors

In Pithos+ atomicity is forced on the container level.
Hence, write operations in the account level can produce
integrity errors.

This commit handles these cases.

In PostgreSQL, a transaction is aborted
(and all the subsequent commands are ignored)
if an integrity error occurs.

Therefore, before performing an command
that can produce an integrity error,
a new savepoint is defined inside the transaction,
and after the command execution is rollbacked or committed
according to execution status.
docs: Update copyright date on docs
ui: Fix volume details editing controls position
ui: Update resource titles truncation length
astakos: Update checkbox label in terms acceptance form

the field description changed for field description clarity when
displayed in user management commands context resulting confusion when
appeared in terms acceptance form. Fixed by reverting field label in the
terms acceptance form class.
docs: Remove obsolete warnings

closes grnet/synnefo#163
astakos: Use bulk_create to speed up commissions

Update holdings and create provisions and log in bulk when issuing or
resolving commissions to speed up the operation,
astakos: update action logic

The following changes are made to the way actions are validated:

* accept: Accept only unmoderated or rejected users.
* deactivate: Deactivate only moderated users. This includes inactive
  users, solely for the purpose of changing their deactivation reason.
* send_verification_mail: Renew verification code and send it only to
  users with unverified mail.
astakos: Update user logic tests

Update tests according to the changes in activation_backends.py

closes grnet/synnefo#164
pithos: Add missing index

Add index on column 'node' of the ''versions' table.

closes grnet/synnefo#161
pithos: Perform size checks during uploads

Verify the consistency between the declared size
and the object's hashmap during uploads/object updates.