ffserver: move configuration code to separate file

This commit doesn't change any existing logic.
It moves ffserver configuration related code to separate file.
It intends to make maintaining easier.

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
ffserver_config: clean up variable initialization

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
ffserver_conf: factorize parse function per config tag

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
Added STL demuxer and decoder

Signed-off-by: Clément Bœsch <u@pkh.me>
avformat/format: Use av_match_name() instead of list in av_match_ext()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avutil/avstring: Reimplement av_match_list()

av_match_list() is only used for whitelists, fix it so it works with
multi-named formats like "mov,mp4,m4a,3gp,3g2,mj2"

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