Positions were originally done using Point2D/3D to simplify their
transformation using matrices and to some extent simplify their usage in
shaders. But now the disadvantages exceeded the advantages:
* They take 50% more for 2D positions and 33% more for 3D positions, as
last coordinate is always equal to 1, on the other hand when last
coordinate is errorneously not equal to 1 they have crazy behavior.
* Normalizing them or transforming them with anything else than with
matrices is PITA, as we need to strip the last component, do the
transformation, and then add the component back.
* All transformation handling classes (Complex, DualComplex,
Quaternion, DualQuaternion, Matrix3, Matrix4) now have convenience
functions for transforming points specified directly as
Vector2/Vector3 (and also for transforming vectors).
* When someone wants to use homogeneous coordinates with crazy last
component values, they can do so with plain Vector3 for 2D and
Vector4 for 3D and it will be less confusing than using Point2D/3D
which no important detail hidden.
Vector4 doesn't set W component to one by default anymore, this is now
handled by Point*D itself. This finally allows creating of 2D primitives
and 2D position vectors without messing explicitly with Z = 1.
All classes which should use Point instead of Vector were updated to use
Point instead.
Magnum.h now doesn't include anything except OpenGL headers, thus
changes in Math library don't trigger recompilation of everything, but
only of things really depending on it.
Math constants moved to separate file for similar reasons, de-inlined
some functions to remove the need for some #includes.
Vladimír Vondruš