readline: key interval delay for \r & \n

Emit two line events when there is a delay between
CR('\r') and LF('\n').

Introduced a new option `crlfDelay`. If the delay between \r and \n
exceeds `crlfDelay` milliseconds, both \r and \n will be treated as
separate end-of-line input. Default to 100 milliseconds.
`crlfDelay` will be coerced to [100, 2000] range.

PR-URL: https://github.com/nodejs/node/pull/8109


Reviewed-By: Yorkie Liu <yorkiefixer@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>