Fixed failed to install (scottrogowski#72) (scottrogowski#73)

Author: Pandaft

setup.py

@@ -9,7 +9,7 @@
     name='code2flow',
     version=VERSION,
     description='Visualize your source code as DOT flowcharts',
-    long_description=open('README.md').read(),
+    long_description=open('README.md', encoding='utf-8').read(),
     long_description_content_type="text/markdown",
     entry_points={
         'console_scripts': ['code2flow=code2flow.engine:main'],