renamed cli to just pytube

pep8, removed calls to deprecated methods.

Default to cwd for path arg

- added import print_function from __future__ for backward compatibility to 2.6

- ported to 3.4.1 with backward compatibility

Add missing whitespace between operators

Whitespace cleanup

added exit call when either resolution or extension is missed

covert relative path to absolute path at the time being passed from commad line, updated Downlaoding message to print where the file is saved to, check to make sure user passes both extension and resolution and print to shell if not sure what resolution to choose, and fix for progress bar dispay on windows.

added progress bar, and function to read size in human readable format, updated call to print_status function

rearranged imports in cli

renamed res arg to resolution for consistancy, moved pytube cli into repository root, renamed it pytubectl