modernized the package and improved python 3 support

added more widgets, dropped python 2.6 support and improved testing

fixed jupyter notebook, last update and negative ETA bugs thanks to @…

…zzzsochi v3.6.1

Fixed progressbar on Windows consoles

Fixed documentation for resizing and made the progressbar a little fa…

…ster in case of many updates. Thanks to @max-arnold for the patches!'

removed debug code, the exception shouldnt raise v3.5.1

Added size-dependent widgets

Removed debug statement

Fixed auto width

fixed terminal size detection bugs v3.4.1