New security model, faster song switching in Subsonic 2.5

Changes in Subsonic 2.5:

New: Implemented user management. Users are easily created, deleted and assigned different privileges.

New: Faster song switching. Players react immediately to playlist changes.

New: Now possible to refine search for cover art and album info.

New: Better support for OGG, AAC and other formats. Added proper suffix to stream URL as a hint to the player.

New: Display media library statistics.

New: New location for preferences, search index and database (c:\subsonic or /var/subsonic).

Bugfix: Improved parsing of MP3 tags. Avoid funny characters in artist, album and song title.