Move from libavresample to libswresample

Move from libavresample to libswresample

  - The libavresample as part of FFmpeg was declared as deprecated in
    favor of libswresample on Dec 25 2017 in commit "lavr: deprecate the
    entire library"
    (https://github.com/FFmpeg/FFmpeg/commit/c29038f3041a4080342b2e333c1967d136749c0f
    ;
    https://git.ffmpeg.org/gitweb/ffmpeg.git/commitdiff/c29038f3041a4080342b2e333c1967d136749c0f).
    As major Linux distributions (RPM, DEB and Archlinux) provide now
    FFmpeg and libswresample as its part use the libswresample instead of
    libavresample.

Signed-off-by: Vladimir Lomov <vladimir@smoon7.vl-lomov.ru>