Fixed bug in MP3 importer with ID3 data

git-svn-id: http://svn.code.sf.net/p/gpac/code/trunk/gpac@5560 63c20433-aa62-49bd-875c-5a186b69a8fb
fixed bug with cache and onDemand files

git-svn-id: http://svn.code.sf.net/p/gpac/code/trunk/gpac@5561 63c20433-aa62-49bd-875c-5a186b69a8fb