Add triangle SAT intersection

include/J3ML/Geometry/Common.h

@@ -27,5 +27,13 @@ namespace J3ML::Geometry
 // Methods required by Geometry types
 namespace J3ML::Geometry
 {
+    // Represents a segment along an axis, with the axis as a unit
+    struct Interval {
+        float min;
+        float max;
 
+        bool Intersects(const Interval& rhs) const;
+
+        bool operator==(const Interval& rhs) const = default;
+    };
 }