parser/mp3: Add support for detecting an initial id3v2 tag
parser/mp3: Add support for detecting an initial id3v2 tag

* Look for 'ID3' while looking for the 0xFF's to start an audio frame
* Fix some aspects of the id3v2 code

pteich/StreamMachine,pedropapa/StreamMachine,DreamNetwork/StreamMachine,cdgraff/StreamMachine,SCPR/StreamMachine,DreamNetwork/StreamMachine,StreamMachine/StreamMachine,cdgraff/StreamMachine,pteich/StreamMachine,pedropapa/StreamMachine,SCPR/StreamMachine,StreamMachine/StreamMachine