Listing wireless networks

[daguy666]

If en0 is not the default wireless interface.

Traceback (most recent call last):
  File "./main.py", line 73, in <module>
    IS.main()
  File "/Users/<username>/git/Transit/utils/info_scan.py", line 48, in main
    self.build_up_system_info()
  File "/Users/<username>/git/Transit/utils/info_scan.py", line 41, in build_up_system_info
    for wifi in self.gsi.return_wireless_networks():
TypeError: 'NoneType' object is not iterable