Bugfix/corbett bytestostring :: Python3 Support

[asciifaceman]

Sorry for the commit spam - squash on merge to clean that up.

• Python3 support

Tested on 3.8.5

Python3 introduces more aggression around the difference between str and bytes, apparent in a few operations degoss.py was performing

---

• Update binary download to just use shutil - it is chunking and buffering in the background anyways and response is a file-like object (response.read() becomes bytes in py3 and it was having encoding issues)
• Update subprocess to use utf8 encoding (IO becomes bytes in py3)

---- Should fix #47