WIP: Initial GUI work

examples/gui_state.cr

@@ -0,0 +1,29 @@
+require "./../src/cyberarm_engine"
+
+class Window < CyberarmEngine::Window
+  class State < CyberarmEngine::GuiState
+    @options : Int32
+
+    def setup
+      stack(width: 100, height: 100.0) do
+        background 0xff_353535
+
+        title "Hello World"
+      end
+    end
+
+    def draw
+      Gosu.draw_rect(0, 0, window.width, window.height, 0xff_353535)
+    end
+
+    def needs_cursor?
+      true
+    end
+  end
+
+  def setup
+    push_state(State.new(3))
+  end
+end
+
+Window.new.show