Attempt to remedy install problems from 0.4.0

Relates to 1436fb3ef4

setup.py

@@ -15,6 +15,15 @@ with codecs.open(os.path.join(os.path.abspath(os.path.dirname(
     except IndexError:
         raise RuntimeError('Unable to determine version.')
 
+install_requires = [
+    'httptools>=0.0.9',
+    'ujson>=1.35',
+    'aiofiles>=0.3.0',
+]
+
+if os.name != 'nt':
+    install_requires.append('uvloop>=0.5.3')
+
 setup(
     name='sanic',
     version=version,
@@ -22,15 +31,11 @@ setup(
     license='MIT',
     author='Channel Cat',
     author_email='channelcat@gmail.com',
-    description='A microframework based on uvloop, httptools, and learnings of flask',
+    description=(
+        'A microframework based on uvloop, httptools, and learnings of flask'),
     packages=['sanic'],
     platforms='any',
-    install_requires=[
-        'uvloop>=0.5.3;platform_system!="Windows"',
-        'httptools>=0.0.9',
-        'ujson>=1.35',
-        'aiofiles>=0.3.0',
-    ],
+    install_requires=install_requires,
     classifiers=[
         'Development Status :: 2 - Pre-Alpha',
         'Environment :: Web Environment',