Bump up version to 0.1.6

Author: yanyin1986

build.gradle

@@ -45,7 +45,7 @@ publishing {
 
     publications {
         maven(MavenPublication) {
-            version '0.1.5'
+            version '0.1.6'
             group 'org.mushare'
             from components.java
         }

src/main/java/org/mushare/pluto/Pluto.java

@@ -9,12 +9,10 @@
 import java.io.UnsupportedEncodingException;
 import java.security.Signature;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Base64;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
-import java.util.stream.Stream;
 
 public class Pluto {