PKG: Add setuptools dependency

`arabic_reshaper.py` makes use of `pkg_resources`, which is part of `setuptools` (which, in turn, are not part of the Python standard library).

Author: hoechenberger

setup.py

@@ -21,7 +21,7 @@
     platforms="ALL",
     license="GPL",
     packages=['arabic_reshaper'],
-    install_requires=['configparser', 'future'],
+    install_requires=['configparser', 'future', 'setuptools'],
     author="Abdullah Diab",
     author_email="[email protected]",
     maintainer="Abdullah Diab",