Initial work on ledge & improved baking of root motion. (#90)

Reviewed-on: #90
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/math/rect.rs

@@ -0,0 +1,12 @@
+use crate::math::vec::FGVec2;
+
+pub struct FGRect {
+    pub origin: FGVec2,
+    pub end: FGVec2,
+}
+
+impl FGRect {
+    pub fn contains_point(&self, point: FGVec2) -> bool {
+        point.x >= self.origin.x && point.y <= self.origin.y && point.x <= self.end.x && point.y >= self.end.y
+    }
+}