Upgrade python to Spark 2.3

Author: holdenk

requirements.txt

@@ -1,5 +1,5 @@
 coverage
-pyspark>=2.2.0
+pyspark>=2.3.0
 pypandoc
 scipy
 numpy
@@ -8,3 +8,5 @@ unittest2>=1.0.0
 pandas>=0.13
 spacy
 future
+pyarrow==0.8.0
+pep8

setup.py

@@ -15,11 +15,12 @@
     description='Add additional ML algorithms to Spark',
     long_description=open('README.md').read(),
     install_requires=[
-        'pyspark>=2.2.0',
+        'pyspark>=2.3.0',
         'numpy', # Requires for PySpark ML
         'pandas',
         'spacy',
         'future',
+        'pyarrow',
     ],
     test_requires=[
         'nose==1.3.7',