cyclades: Forbid deleting port from suspended vms

Check if a VM is administratively suspended before deleting it's port.
pithos: Refactor statistics subquery

Use CTE to get current population.

Add partial index to versions table.
pithos: Add missing setting from conf
pithos: Fix issues with groups

* Apply checks for group name/member length
* Do not try to insert an existing member to a group (integrity error)
pithos: pep8 fixes

closes grnet/synnefo#172
Update Cyclades section in Changelog
Fix typo
Bump version to 0.16next
settings infrastructure
astakos services and urls
astakos settings
chain
branding fix in astakos
astakos setup
services infrastructure
astakos services/urls tests
cyclades services and urls
service infrastructure more
cyclades setup
cyclades settings