The args struct is reused to attempt opening an URL with
different stream layers, overwriting args->url not only
breaks this but also causes the freed buffer to be used again.
Add support for reading a byte range from a stream via
the `slice://` protocol.
Syntax is `slice://start[-end]@URL` where end is a maximum
(read until end or eof).
Size suffixes support in `m_option` is reused so they can
be used with start/end.
This can be very useful with e.g. large MPEGTS streams with
corruption or time-stamp jumps or other issues in them.
Signed-off-by: Mohammad AlSaleh <CE.Mohammad.AlSaleh@gmail.com>
