Log Message:
py-urwid: updated to 2.1.1

Urwid 2.1.1
* Add TrioEventLoop.run_async(), removed nursery constructor arg
* Add py38 to Travis tests
* Add popular IDEs folders to .gitignore
* Add wrap_around kwarg to SimpleListWalkers
* Change documentation on Terminal
* Remove debug documentation change test
* Remove support for py34
* Remove invalid escape sequence
* Fix GridFlow keypress handling when v_sep is 0
* Fix Terminal in ListBox
* Fix Crash on `fg`, SIGCONT (after Ctrl-Z, SIGSTOP, SIGTSTP)
* Fix 256-color mode on some terminals.
* vterm: reduce __init__ boilerplate
* vterm: errno 5 is not EOF.
* Terminal: use UTF-8 by default.
* Instance of Terminal has no __super attr -- thanks pylint!
* Do not call wait_readable with a closed fd in TrioEventLoop
* Make options a static method where applicable
* Set up Travis to run py38, speed up build