Make pytubectl work; change print to print() as it's apparently supposed to be python3
Change cipher function to use external js interpreter, so it works again

You'd want to install e.g. spidermonkey for this to work
Make download() return status code: A lib shouldn't terminate the running application if something goes wrong.
Adapt to changed JS
replaced unstable JavaScript Cipher Signature execution code with PyExecJS library, which tries to use different JavaScript engines directly
Merge pull request #1 from Timtam/master

replaced unstable JavaScript Cipher Signature execution code with PyExecJS library, which can access 4 different JavaScript engines on the fly
- integrated all commits from NFicano main project until up-to-date
Merge pull request #2 from Timtam/master

- integrated all commits from NFicano main project until up-to-date
Merge branch 'master' of https://github.com/Zahl/pytube

Conflicts:
	pytube/api.py
	pytube/models.py
	pytube/tinyjs.py
	release
	scripts/pytubectl