v2.8.0

v2.8.0, 2017-04-02

Source code cleanup, test refactor, new strategies and improved __repr__ of
strategies

• Improved/refactored source code:
  #917
  #952
• Internal improvement: remove the init_args decorator as superseded by the
  kward_args:
  #918
• Strategy __repr__ now automatically includes all parameters of a strategy:
  #953
  #922
• Type hints:
  #883
  #935
  #949
  #951
• Refactor of tests:
  #924
  #927
  #928
  #933
  #934
  #937
• New strategy: SlowTitForTwoTats2
  #926
• New strategy: GeneralSoftGrudger
  #936

Here are all the commits for this PR:
v2.7.0...v2.8.0