Log Message:
libshout: update to 2.4.2.

libshout 2.4.2 (20190429)

* Fixed handling of invalid characters in strings:
  * Correctly escape mountpoint names (#2233),
  * Correctly escape mountpoint names and passwords in deprecated metadata API \ 
(#2304),
  * Do not allow ICE headers with invalid characters (#2302).
* Fixed and updated build system.
* Allow building libshout on Android.
* Rewrote TLS handling code and statemachine (#2244, #2298, #2301, #2303).
* Support OPTIONS for RFC 2817 TLS mode.
* Allow manual inspection of server's TLS certificate.
* Updated documentation.