Add codecs from avcodec.h
Add codecs from avcodec.h

From: https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/avcodec.h

Generated with gcc: gcc -fdump-go-spec=out.go avcodec.h

Extracted with: grep 'const _AV_CODEC_ID_' out.go

targodan/ffgopeg,giorgisio/goav,targodan/ffgopeg,piotrrojek/goav,targodan/ffgopeg