ENH: add contextlib2 as py2 only dependency

MANIFEST.in

@@ -2,6 +2,7 @@ recursive-include blaze *.py
 recursive-include docs *.rst
 
 include requirements-strict.txt
+include requirements-py2.txt
 include setup.py
 include README.rst
 include LICENSE.txt

blaze/compatibility.py

@@ -60,6 +60,7 @@ def boundmethod(func, instance):
         return MethodType(func, instance, type(instance))
 
     from itertools import izip_longest as zip_longest
+    from contextlib2 import ExitStack
 else:
     _inttypes = (int,)
     _strtypes = (str,)
@@ -68,6 +69,7 @@ def boundmethod(func, instance):
     boundmethod = MethodType
 
     from itertools import zip_longest
+    from contextlib import ExitStack
 
 
 import io

requirements-py2.txt

@@ -0,0 +1,2 @@
+# backport of ExitStack
+contextlib2

setup.py

@@ -53,7 +53,12 @@ def find_data_files(exts, where='blaze'):
     longdesc = f.read()
 
 with open('requirements-strict.txt') as f:
-    install_requires = f.read().strip().split('\n')
+    install_requires = f.read().strip().splitlines()
+
+
+if sys.version_info[0] == 2:
+    with open('requirements-py2.txt') as f:
+        install_requires.extend(f.read().strip().splitlines())
 
 
 setup(