Add zsh completion
Shorten parts of the quickhelp
Merge branch 'quickhelp' of https://github.com/holomorph/transmission-remote-cli
Empty stdin when closing window

Multibyte key sequences (e.g. F1) start with escape, which closes the window,
and then go on. Any further input is now cleared before closing windows so it
isn't interpreted as user input.

Closes #139
Reduce halfdelay only when clearing user input