CDB-2566 refactored to better names in preparation for new privacy with link type
CDB-2566 Added table new privacy value 'public with link'. still without tests and not all code checked, but passing most existing tests
CDB-2566 small fixes and some specs
CDB-2566 fixed a spec, plus commented two exceptions to avoid problems (sic) although they will still log errors.
Merge remote-tracking branch 'origin/CDB-1604' into CDB-2566

Conflicts:
	app/controllers/api/json/visualizations_controller.rb
CDB-2566 fixed number of datasets to only public ones
CDB-2566 few fixes and more privacy changes to support LINK type
Adds new privacy option for tables (link)