cyclades: Add GANETI_DISKS_WAIT_FOR_SYNC option

Add new setting to denote whether Ganeti will wait for the disk mirror to
sync (DRBD). This setting is used when creating a new instance or adding
a new disk to an existing Ganeti instance.
ui: Fix position of suspended vm notice
docs: Update 0.16 upgrade notes

Describe new Pithos mapfile after the consolidation with Archipelago.
pithos: Add class attribute to ModularBackend

Add _class_version class attribute to ModularBackend class
to differentiate between multiple backend versions.
cloudbar: Do not show image link border in IE