add: error handling and improve logic

add: HLSStream class

Improve HTTP stream chunk reading

add: new ffmpeg transcode method

add: optimized flac stream pipe

add: required dependency

add: migrated opus lib class

update: README.md

add: flac decoder (performance issue) and close event

add: migrated back decoder from audio decoder

add: test for VoolumeTransformer (it's working now)

add: string-based volume transformer and cleanup syntax

add: debug print statements for volumeTransform

push test code

update: [NOT TESTED] complete _transform, _destory, volume settings.