Hides the no_vis when there are no tables.
Merge branch 'develop' of github.com:CartoDB/cartodb20 into develop

* 'develop' of github.com:CartoDB/cartodb20:
  adapt Visualization::Copier spec to Visualization::NameChecker changes
  Refactor Visualization::NameChecker to use VisualizationCollection instead of direct DB access
Merge branch 'develop' of github.com:CartoDB/cartodb20 into develop

* 'develop' of github.com:CartoDB/cartodb20:
  fixed add layer from table