Deprecate Prefs

The Prefs utility class is now deprecated. PrefService should be used
instead.

Author: hinerm

src/main/java/org/scijava/util/Prefs.java

@@ -49,7 +49,9 @@
  * @author Curtis Rueden
  * @author Barry DeZonia
  * @author Grant Harris
+ * @deprecated See {@link PrefService}
  */
+@Deprecated
 public final class Prefs {
 
 	private static PrefService prefService;