Release version 0.5.9

Quick hotfix (7c6b0c6): The "prep" argument was added to the
``grid_search()`, ``test()``, and ``kfold_cross_validation()`` functions
of the ``Evaluation`` class. This argument allow user to disable/enable
the default preprocessing method.

pyss3/__init__.py

@@ -21,7 +21,7 @@
 from functools import reduce
 from six.moves import xrange
 
-__version__ = "0.5.8"
+__version__ = "0.5.9"
 
 ENCODING = "utf-8"