Lplex under revision

Git code of lplex is undergoing changes to remove dependencies to wxWidgets and take advantage of c++17.
Current git code builds and works for simple cases. Lplex-dependent code in dvda-author is currently broken yet should be fixed in early summer.
Related options are: --miror --full-hybridate --mirror-strategy etc, which are used to convert AUDIO_TS into VIDEO_TS and increase portability across hardware.
However lplex-made VIDEO_TS folders can be imported with --videodir and linked to with -T. See EXAMPLES files for test cases.