avformat/matroskadec: Detect conflicting sample rate/default_duration

Fixes Ticket2508

Thanks-to: Moritz Bunkus
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 6158a3bcdf52fafc1d9ae9eb358a56c614b23aa3)
ftp: fix interrupt callback misuse

FTP protocol used interrupt callback to simulate nonblock
operation which is a misuse of this callback.

This commit make FTP protocol fully blocking and removes
invalid usage of interrutp callback

Also adds support for multiline responses delimited with dashes
(cherry picked from commit 247e658784ead984f96021acb9c95052ba599f26)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>