Add de/muxer constructors taking pointer to existing instance

Update readme

Add FrameSideDataList and matching PacketSideDataList

Add utility function to setup log callback

Merge pull request #9 from RyanYANG52/master

Add new filter builder API

Add PacketSideDataList class

Add utility VideoFilterPipeline class

FrameExtractor demo add auto rotate

make colorspace in AddVideoBufferSource mandatory

MediaFilterGraph.AddAudioBufferSource add colorsapce params

MediaDemuxer.Seek() add MediaStream? param to support seeking within a specific stream (#8)

add StreamCopy to MediaMuxer.AddStream; add Remux sample (#7)

Fix JPEG color range conversion in VideoFrame.Save()

Update release workflow