added items per second widget v3.16.0

Made sure even really fast progressbars finish. Fixes wolph#102 v3.15.1

Large performance improvements. Dropped Pypy3 support in Travis tests…

…. Improved output redirection (fixed several bugs). Showing N/A when no numbers are available. v3.15.0

Improved support for sequences with unknown length thanks to @WohthaN

Fixed resizing with nested progressbars

Fixed output redirection with special ipython and jupyter notebook su…

…pport

Fixed Linux integer overflow bug with ETA

Bumped version for pypi

Fixed strange git undo

improved test coverage v3.9.1