Current libavcodec does no longer always return S16 sample format, but
the conversion needs to be done explicitly. Use libswscale for that.
Not tested on raspbian, only on yocto/ffmpeg.
* remove ilclient
* use a decoder implementation similar to pidvbip instead,
see https://github.com/linuxstb/pidvbip
* video is decoded in hardware (videocore)
* audio is decoded by libavcodec
* add a AVDec wrapper class for both audio and video decoders
* very raw, needs more polishing. But decodes audio and video :-)
* only tested with h264