Fix extra newline on muted, replaced input

[deed02392]

The extra newline is redundant, because a new line character is what is entered in order to terminate input anyway.

[satazor]

I just got a bug report on promptly related to this: https://github.com/moxystudio/node-promptly/issues/27

@isaacs @zkat any change we got this merged?

[rvagg]

Fixes: #26

@isaacs any chance you're back in the open source saddle and prepared to land this? it'd be a great help.

[wraithgar]

Rebased in #52