Pointer actions should allow either tilt* or *Angle fields but not both

[jgraham]

These refer to the same thing: https://w3c.github.io/pointerevents/#converting-between-tiltx-tilty-and-altitudeangle-azimuthangle so it doesn't make sense to have both, but instead we should insist that the implementation converts them according to the requirements of that specification.

[jrandolf]

+1