Add new constructor

Author: ianopolous

pom.xml

@@ -4,7 +4,7 @@
 
 	<groupId>io.ipfs</groupId>
 	<artifactId>multihash</artifactId>
-	<version>1.0.0</version>
+	<version>1.1.0</version>
 	<packaging>jar</packaging>
 
 	<name>multihash</name>

src/main/java/io/ipfs/multihash/Multihash.java

@@ -46,6 +46,10 @@ public Multihash(Type type, byte[] hash) {
         this.hash = hash;
     }
 
+    public Multihash(Multihash toClone) {
+        this(toClone.type, toClone.hash); // N.B. despite being a byte[], hash is immutable
+    }
+
     public Multihash(byte[] multihash) {
         this(Type.lookup(multihash[0] & 0xff), Arrays.copyOfRange(multihash, 2, multihash.length));
     }