The terminal CR -> NL mapping setting should be inherited in cbreak mode as OSes do not specify altering it as part of their stty cbreak mode definition.
* tty.setraw() and tty.setcbreak() previously returned partially modified
list of the original tty attributes. Now they return the correct list of
the original tty attributes
* tty.cfmakeraw() and tty.cfmakecbreak() now make a copy of the list of
special characters before modifying it.