Implement extremely basic combat

There's a gormlak, you can kill it.
That's it.

src/entities/mod.rs

@@ -1,3 +1,5 @@
+#[macro_use]
+pub mod entity;
 pub mod character;
 pub mod creature;
 pub mod entity_char;
@@ -5,20 +7,8 @@ pub mod raws;
 
 pub use character::Character;
 pub use creature::Creature;
+pub use entity::{Entity, Identified};
 pub use entity_char::EntityChar;
 pub use raws::raw;
 
-use crate::display::Draw;
-use crate::types::{Positioned, PositionedMut};
-use downcast_rs::Downcast;
-use std::io::{self, Write};
-
-pub trait Entity: Positioned + PositionedMut + Draw + Downcast {}
-
-impl_downcast!(Entity);
-
-impl Draw for Box<dyn Entity> {
-    fn do_draw(&self, out: &mut Write) -> io::Result<()> {
-        (**self).do_draw(out)
-    }
-}
+pub type EntityID = u32;