Add isVisible method

Military-Hero-Core/src/com/annimon/militaryhero/Enemy.java

@@ -13,24 +13,28 @@ public class Enemy {
     private static final int enemyHeight = enemy.getHeight();
     
     private final int x, y;
-    private boolean isVisible;
+    private boolean visible;
 
     public Enemy(int x, int y) {
         this.x = x;
         this.y = y;
-        isVisible = true;
+        visible = true;
+    }
+    
+    public boolean isVisible() {
+        return visible;
     }
     
     public boolean isCollide(int sx, int sy) {
         if (inRange(sx, x, x + enemyWidth) && inRange(sy, y, y + enemyHeight)) {
-            isVisible = false;
+            visible = false;
             return true;
         }
         return false;
     }
     
     public void draw(Graphics g) {
-        if (isVisible) {
+        if (visible) {
             g.drawImage(enemy, x, y);
         }
     }