Added some 1-second sleeps to acceptance testing to give time for animations to finish before trying to operate on page elements. Specifically the appearing- and disappearing-animation of the "add subscription" popup was sometimes causing trouble, because Capybara sometimes tried to fill values on the form before it was shown.
Lowered log level in the continuous integration environment to Info.

We were having so many logs that Travis was complaining; besides, it was impossible to find anything in such a verbose log.