avio access: use new API
avio access: use new API

- fix bug in ACCESS_GET_PTS_DELAY where it would fall through the next case
- print error messages from libavformat
- remove useless strdup
- check for exclusive access to avio when context open succeeded
- support for multiple input / output at the same time with libavformat > 54 (untested)

vlc-mirror/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc,vlc-mirror/vlc,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,xkfz007/vlc,krichter722/vlc,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,krichter722/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,krichter722/vlc,jomanmuk/vlc-2.2,krichter722/vlc,shyamalschandra/vlc,krichter722/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.2,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.2,krichter722/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.1,krichter722/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,vlc-mirror/vlc,jomanmuk/vlc-2.1