Added setup.py. Run: python -m wifite

As asked by @blshkv in #102.

Running: `sudo python -m wifite`
Install: `sudo python setup.py install`

These steps (and "uninstalling") are mentioned in the README.

bin/wifite

@@ -0,0 +1,4 @@
+#!/usr/bin/env python
+
+from wifite import __main__
+__main__.entry_point()