Get interface automatically (don't hardcode it)

[prateekmedia]

We can get the default interface easily by running this command:

ip -4 route ls | grep default | grep -Po '(?<=dev )(\S+)'

So hardcoding wifi interface is not needed.

[jmanc3]

@prateekmedia interface should be automatically detected after commit 98d2077. Let me know!

[prateekmedia]

@jmanc3 Thanks, it is fixed now. Although I thought that this will also fix #33 but no it still persists :(