7DRL 2024 Day 4 updates - UIGrid / mcrfpy.Grid

Massive new set of behaviors:
* Move, resize*, zoom, and pan mcrfpy.Grid instances from Python. Note:
there's a rendering error with resizing, which will have to wait for
after 7DRL.

* Add, remove, and create mcrfpy.Entity instances from Python. The
fields can be edited to change position and sprite. They can be removed
from a grid and/or added to another. the Entity class is closely related
to the EntityCollection class, the Python interface to UIGrid's
std::vector of UIEntities.

* mcrfpy.GridPoint and mcrfyp.GridPointState objects. The GridPoint
class allows access to the "physical" parts of a grid. The
GridPointState class allows access to an entity's knowledge of it. Grids
and Entities have an "at" method that takes a tuple (x,y) and returns
one of these objects.

__repr__ and many other nice things are notably absent - many TODOs were
added to the codebase today. They can get picked up after 7DRL.

src/UITestScene.cpp

@@ -119,7 +119,8 @@ UITestScene::UITestScene(GameEngine* g) : Scene(g)
     //UIEntity test:
     // asdf
     // TODO - reimplement UISprite style rendering within UIEntity class. Entities don't have a screen pixel position, they have a grid position, and grid sets zoom when rendering them.
-    auto e5a = std::make_shared<UIEntity>(); // default constructor sucks: sprite position + zoom are irrelevant for UIEntity.
+    auto e5a = std::make_shared<UIEntity>(*e5); // this basic constructor sucks: sprite position + zoom are irrelevant for UIEntity.
+    e5a->grid = e5;
     auto e5as = UISprite(indextex, 85, sf::Vector2f(0, 0), 1.0);
     e5a->sprite = e5as; // will copy constructor even exist for UISprite...?
     e5a->position = sf::Vector2f(1, 0);