Restore copyright year.

[ci skip]

Source/Urho3D/Core/Spline.h

@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2008-2014 the Urho3D project.
+// Copyright (c) 2008-2015 the Urho3D project.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal