http: Remove an unrelated and mistakenly set AVOption unit name

This was due to a copypaste oversight.

Signed-off-by: Martin Storsjö <martin@martin.st>
http: Support relative URL redirection

In RFC 2616, this was explicitly said to be an absolute URL,
while in an upcoming draft [1] it is allowed to be relative as well.

[1] http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-25#section-7.1.2

Signed-off-by: Martin Storsjö <martin@martin.st>
http: Expose the content location via an AVOption

Signed-off-by: Martin Storsjö <martin@martin.st>
hls: Check whether the AVIOContext contains a new redirected URL

This allows both the main playlist itself as well as the variant
playlists to handle redirects combined with relative URLs.

Signed-off-by: Martin Storsjö <martin@martin.st>
hls: Avoid reading outside of the allocated array

CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>