python 3 support

[Sispheor]

As the end of python 2 is near, would be nie to convert this app to python 3.

[bovender]

Yeah, I noticed that when I set up a new virtual machine with Ubuntu 19.04 to develop this applet. (My main machine is a KDE neon system.) However, I'm really not very experienced at all with Python GUI programming. If someone (you...?!) could assist with upgrading this project to Python 3, that would be great.

Kind regards

Daniel

[Sispheor]

I sent a PR for this.

[bovender]

Anyone coming here looking for Python3 support should look at Sispheor's remake of this applet:

https://github.com/Sispheor/indicator-ip

See also: #17 (comment)