Autoset hardware acceleration

[Neraste]

Hardware decoding in VLC is critical if all components of the Dakara project are run on the same computer. However, this has to be set manually with the avcodec-hw parameter by the user, who has to choose the correct argument depending on their hardware and operating system.

Hardware acceleration settings should be done directly by the program, in the constructor of VlcPlayer.

While the hardware detection is not a problem on Linux, it certainly will be on Windows… See this question.