Add NSURLIsExcludedFromBackupKey to libspotify directories (GitHub issue #168)

Change-Id: Ifb5eb235a1e22a13b9b09c01f7984761a58881c2
Update CHANGELOG and documentation for 2.4.5 release

Change-Id: I60444534311ff71272725964b679aacaa34a21c2
Merge branch 'icloud-backup-fix' for 2.4.5 release.

Change-Id: I46c6f1e36d2c78663fc7e4e80f08b4e6edbe47d3