Move Jedis CRC16 util as it's being used in the project.

Changed Makefile to cleanup redis cluster node configuration before running tests
Add cleanup to ClusterCommandTest.

src/main/java/redis/clients/util/JedisClusterCRC16.java

@@ -0,0 +1,21 @@
+package redis.clients.util;
+
+public class JedisClusterCRC16 {
+	public final static int polynomial = 0x1021;	// Represents x^16+x^12+x^5+1
+	static int crc;
+	
+	public static int getSlot(String key) { 
+		crc = 0x0000;
+        for (byte b : key.getBytes()) {
+            for (int i = 0; i < 8; i++) {
+                boolean bit = ((b   >> (7-i) & 1) == 1);
+                boolean c15 = ((crc >> 15    & 1) == 1);
+                crc <<= 1;
+                // If coefficient of bit and remainder polynomial = 1 xor crc with polynomial
+                if (c15 ^ bit) crc ^= polynomial;
+             }
+        }
+
+        return crc &= 0xffff % 16384;
+    }	
+}