Fix XML API tag info (fix #281)
Added "real"-hover buttons for the sidebar..

..you do not have to click precisely on the text. The buttons now have a 100% width so you can better navigate.
Add Sort Tracks by Artist, Album, Song on playlists (fix #279)
Fix Browse page TextBox footer
Add CONTRIBUTING.md file
Add DAAP protocol support (fix #272)
DAAP session become optional
Fix byte range request response

Example range request: "Range: bytes=2582528-"
would return response: "Content-Range: bytes 2582528-0/2583490"
as $end stayed 0.
Fix DAAP streaming rang and code type (now working with Winamp DAAP plugin)
Fix user online/offline indication in Reborn theme (fix #298)
Restore legacy xml api tags node
Fix codestyle
Concat folder.jpg with DIRECTORY_SEPARATOR define