Added AverageWindEncoder.

Refactored AverageWindDecoder - it now implements MessageDecoder.
Refactored AverageWind - it now uses milliseconds and knots, instead of packed MMperSec and tenths of a second. It also exposes its attributes now.
Added (un)packAverageWindPeriod to AC35UnitConverter.
Added AverageWindDecoderTest.
issue #35 #36
#story[1095]

racevisionGame/src/test/java/network/MessageDecoders/AverageWindDecoderTest.java

@@ -0,0 +1,75 @@
+package network.MessageDecoders;
+
+import network.MessageEncoders.RaceVisionByteEncoder;
+import network.Messages.AverageWind;
+import static org.junit.Assert.*;
+import org.junit.Test;
+import shared.model.Bearing;
+
+import java.util.ArrayList;
+
+/**
+ * Test for the AverageWind encoder and decoder
+ */
+public class AverageWindDecoderTest {
+
+
+    /**
+     * Creates a AverageWind message, encodes it, decodes it, and checks that the result matches the starting message.
+     * @throws Exception if test fails.
+     */
+    @Test
+    public void averageWindEncodeDecodeTest() throws Exception {
+
+        AverageWind averageWind = new AverageWind(
+                AverageWind.currentMessageVersionNumber,
+                System.currentTimeMillis(),
+                3000,
+                12.5,
+                4050,
+                12.6,
+                3055,
+                12.7,
+                6051,
+                13.37
+        );
+
+        byte[] encodedMessage = RaceVisionByteEncoder.encode(averageWind);
+
+        AverageWindDecoder averageWindDecoder = new AverageWindDecoder();
+        averageWindDecoder.decode(encodedMessage);
+        AverageWind averageWindDecoded = averageWindDecoder.getMessage();
+
+        compareAverageWindMessages(averageWind, averageWindDecoded);
+
+    }
+
+
+    /**
+     * Compares two AverageWind messages to check that they are equal.
+     * @param original The original AverageWind message.
+     * @param decoded The decoded AverageWind message.
+     */
+    public static void compareAverageWindMessages(AverageWind original, AverageWind decoded) {
+
+
+        assertEquals(original.getMessageVersionNumber(), decoded.getMessageVersionNumber());
+        assertEquals(original.getTime(), decoded.getTime());
+
+        assertEquals(original.getRawPeriod(), decoded.getRawPeriod(), 100);
+        assertEquals(original.getRawSpeedKnots(), decoded.getRawSpeedKnots(), 0.01);
+
+        assertEquals(original.getSampleTwoPeriod(), decoded.getSampleTwoPeriod(), 100);
+        assertEquals(original.getSampleTwoSpeedKnots(), decoded.getSampleTwoSpeedKnots(), 0.01);
+
+        assertEquals(original.getSampleThreePeriod(), decoded.getSampleThreePeriod(), 100);
+        assertEquals(original.getSampleThreeSpeedKnots(), decoded.getSampleThreeSpeedKnots(), 0.01);
+
+        assertEquals(original.getSampleFourPeriod(), decoded.getSampleFourPeriod(), 100);
+        assertEquals(original.getSampleFourSpeedKnots(), decoded.getSampleFourSpeedKnots(), 0.01);
+
+
+    }
+
+
+}