Improve math module (#396)

* Improve math module

- Mark almost everything constexpr
- Equality (a == b) is now exact, down to the bit level. If you want approximate equality use the new ApproxEqual method/static method
- Rename Nz::Extend to Nz::Extent
- Removed Make[] and Set[] methods in favor of their static counterpart and operator=

tests/UnitTests/Engine/Math/PlaneTest.cpp

@@ -16,11 +16,6 @@ SCENARIO("Plane", "[MATH][PLANE]")
 				REQUIRE(firstPlane == secondPlane);
 			}
 
-			AND_THEN("We compare with normal(-1, -1, -1), distance -1")
-			{
-				REQUIRE(firstPlane == Nz::Planef(-Nz::Vector3f::Unit().Normalize(), -1.f));
-			}
-
 			AND_THEN("They have the same distance from the same point")
 			{
 				Nz::Vector3f point(-2.f, 3.f, 1.f);