minor fixes to "byte" strings decode, and adaptation to use as a module

[jedzill4]

minor fix to citation error in python3 (TypeError: can't concat bytes to str) (issue #33 #39 #40) thanks to @hinnefe2 for the general fix. Minor change on function/exception names to full compativility as a module.

[ckreibich]

Wow, thanks so much for putting so much work into this! I will try me best to review this soon ... as you can tell it's been hard for me to keep up with the pull requests here.