Ability to knock on doors and windows

[Stormc12]

I always thought the idea of adding the ability to knock on doors would be a good idea, as a way of getting the attention of zombies inside so you can tell whether or not there may be zed waiting behind the door. Simple, but a possible life saver!

[Kalista]

Right now you can hit the melee attack button to shove the door and get the same effect I've used it several times if i suspected a zombie was on the other side and got results of them banging on it right after.