Rerun all tests in watch mode by simply tying 'r' (no enter)

[novemberborn]

Currently, to rerun all tests in watch mode, you need to type r + Enter. It'd be even quicker if you could type r.

See https://nodejs.org/api/tty.html#tty_rs_setrawmode_mode. This seems to intercept Ctrl+C and otherwise mess with the shell, however. But maybe I'm doing something wrong.

Code: https://github.com/sindresorhus/ava/blob/1868204c1901f45b4f66a520ef6486fdd71fe1d2/lib/watcher.js#L116