Improves vis block style
Removes innecesary blocks
Merge branch 'develop' of github.com:CartoDB/cartodb20 into develop

* 'develop' of github.com:CartoDB/cartodb20:
  add maintenance page
  fixed Vizzuality/cartodb-management#2309
  nokia image as default background for basemap dropdown
Improves mapviews message. Closes Vizzuality/cartodb-management#2620gs
Adds tipsy styles
Merge branch 'develop' of github.com:CartoDB/cartodb20 into develop

* 'develop' of github.com:CartoDB/cartodb20:
  fixed Vizzuality/cartodb-management#2531
  fixed Vizzuality/cartodb-management#2644
  fixed problems cleaning buttons in layer panel view - fixes vizzuality/cartodb-management#2660
  trying to fix new bugs in layer panel view
  register table dependencies after creating a data layer
  fixed Vizzuality/cartodb-management#2309
Fixes spec