astakos: Remove unused file admin/users.py
ui: Remove UI_SNAPSHOTS_ENABLED setting

in favor of CYCLADES_SNAPSHOTS_ENABLED setting.
ui: Consistent display of snapshot selection categories

preserve disk creation snapshot categories and their ordering exactly as
they appear in vm create wizard.
pithos: Fix bug when copying mapfiles

All Archipelago resources contain hexlified objects so after
copying or moving a Pithos object representing a snapshot
the new mapfile should contain the same hexlified objects.
docs: Fix typo in CentOS installation guide
deploy: Remove '~okeanos' reference from settings

Change the 'ASTAKOS_NAME' setting value from '~okeanos' to 'Synnefo'