Merge pull request #347 from nsoranzo/setup_fixes

 Add wcwidth for setuptools>=18 and build universal wheels

Author: tleonhardt

setup.cfg

@@ -0,0 +1,2 @@
+[bdist_wheel]
+universal = 1

setup.py

@@ -69,6 +69,7 @@
 EXTRAS_REQUIRE = {
     # Windows also requires pyreadline to ensure tab completion works
     ":sys_platform=='win32'": ['pyreadline'],
+    ":sys_platform!='win32'": ['wcwidth'],
     # Python 3.4 and earlier require contextlib2 for temporarily redirecting stderr and stdout
     ":python_version<'3.5'": ['contextlib2'],
     # Python 3.3 and earlier require enum34 backport of enum module from Python 3.4