Added encodeURIComponent() on the file path url

base64_encode() produces "+" that php will treat as whitespace when decoded into $_GET, then base64_decode() fails. i encounterd this when file names contains multibyte characters.
Added encodeURIComponent() on file and dir url

Urls inside flashvars need to be double escaped.
Update class.AudioPreviewer.js
Update class.SMPlayer.js
Merge pull request #583 from lkho/develop

Added encodeURIComponent() on the file path url for reading mp3