Implement Closeable for Jedis, BinaryJedis etc.

This allows a Jedis object to participate in try-with-resources when
using Java 7+. This change is fully backwards compatible to Java 6 and
previous releases of the Jedis client.

src/main/java/redis/clients/jedis/BinaryClient.java

@@ -948,6 +948,12 @@ public class BinaryClient extends Connection {
 	super.disconnect();
     }
 
+    @Override
+    public void close() {
+	db = 0;
+	super.close();
+    }
+
     public void resetState() {
 	if (isInMulti())
 	    discard();