Return correct hasLineOfSight value for players. Fixes BUKKIT-4634

Prior to this change when a plugin called Player.hasLineOfSite() the
method would always return false because EntityHuman does not extend
EntityInsentient. This commit changes that by explicitly checking for
line of sight between two entities and returning that value.

src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java

@@ -329,7 +329,7 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
     }
 
     public boolean hasLineOfSight(Entity other) {
-        return getHandle() instanceof EntityInsentient && ((EntityInsentient) getHandle()).getEntitySenses().canSee(((CraftEntity) other).getHandle());
+        return getHandle().o(((CraftEntity) other).getHandle());
     }
 
     public boolean getRemoveWhenFarAway() {