Slightly optimised code style and add more functionality

- optimised UI
- check conflicts when change key bind if the key has already been in use
- abstract keybind as a separate singleton class so all class can access it
- [WIP] turning mode is need to be finished

#story[1245]

src/main/java/seng302/model/KeyAction.java

@@ -0,0 +1,35 @@
+package seng302.model;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public enum KeyAction {
+    ZOOM_IN(1),
+    ZOOM_OUT(2),
+    VMG(3),
+    SAILS_STATE(4),
+    TACK_GYBE(5),
+    UPWIND(6),
+    DOWNWIND(7);
+
+    private final int type;
+    private static final Map<Integer, KeyAction> intToTypeMap = new HashMap<>();
+
+    static {
+        for (KeyAction type : KeyAction.values()) {
+            intToTypeMap.put(type.getValue(), type);
+        }
+    }
+
+    KeyAction(int type) {
+        this.type = type;
+    }
+
+    public static KeyAction getType(int value) {
+        return intToTypeMap.get(value);
+    }
+
+    public int getValue() {
+        return this.type;
+    }
+}