Log Message:
Update ruby-highline to 1.6.19.

== 1.6.19

* Fixed `terminal_size()` with jline2 (by presidentbeef).

== 1.6.18

* Fixed a long supported interface that was accidentally broken with a recent \ 
change (by Rubem Nakamura Carneiro).

== 1.6.17

* Added encoding support to menus (by David Lyons).
* Some minor fixes to SystemExtensions (by whiteleaf and presidentbeef).