Move all the interface stuff to interface.Interface

Draw three windows with frames:
- map window
- info window (hit point bar; turn count)
- message window

Clean up the UI code in the Engine.

erynrl/interface/window.py

@@ -0,0 +1,25 @@
+# Eryn Wells <eryn@erynwells.me>
+
+from tcod.console import Console
+
+from ..geometry import Rect
+
+
+class Window:
+    def __init__(self, bounds: Rect, *, framed: bool = True):
+        self.bounds = bounds
+        self.is_framed = framed
+
+    @property
+    def drawable_area(self) -> Rect:
+        if self.is_framed:
+            return self.bounds.inset_rect(1, 1, 1, 1)
+        return self.bounds
+
+    def draw(self, console: Console):
+        if self.is_framed:
+            console.draw_frame(
+                self.bounds.origin.x,
+                self.bounds.origin.y,
+                self.bounds.size.width,
+                self.bounds.size.height)