Changed IdGenerator constructor to accept size instead of end index

src/main/java/envoy/data/IdGenerator.java

@@ -23,12 +23,12 @@ public class IdGenerator implements Serializable {
 	 * Creates an instance of {@link IdGenerator}.
 	 *
 	 * @param begin the first ID
-	 * @param end   the last ID
+	 * @param size  the amount of IDs to provide
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public IdGenerator(long begin, long end) {
+	public IdGenerator(long begin, long size) {
 		current	= begin;
-		this.end	= end;
+		end		= begin + size;
 	}
 
 	@Override