tox: Update hypothesis to 1.12.0.

- Significantly improved performance of creating strategies using the functions
  from the hypothesis.strategies module by deferring the calculation of their
  repr until it was needed. This is unlikely to have been an performance issue
  for you unless you were using flatmap, composite or stateful testing, but for
  some cases it could be quite a significant impact.
- A number of cases where the repr of strategies build from lambdas is improved
- Add dates() and times() strategies to hypothesis.extra.datetimes
- Add new 'profiles' mechanism to the settings system
- Deprecates mutability of Settings, both the Settings.default top level
  property and individual settings.
- A Settings object may now be directly initialized from a parent Settings.
- @given should now give a better error message if you attempt to use it with a
  function that uses destructuring arguments (it still won't work, but it will
  error more clearly),
- A number of spelling corrections in error messages
- py.test should no longer display the intermediate modules Hypothesis
  generates when running in verbose mode
- Hypothesis should now correctly handle printing objects with non-ascii reprs
  on python 3 when running in a locale that cannot handle ascii printing to
  stdout.
- Add a unique=True argument to lists(). This is equivalent to unique_by=lambda
  x: x, but offers a more convenient syntax.

tox.ini

@@ -25,7 +25,7 @@ deps =
     pytest-sugar==0.5.1
     pytest-travis-fold==1.0.1
     xvfbwrapper==0.2.5
-    hypothesis==1.11.4
+    hypothesis==1.12.0
     coverage==4.0.1
     pytest-cov==2.2.0
     beautifulsoup4==4.4.1