My attempt to improve RotatePointAroundVector and VectorNormalize functions in q_math.c

[suijingfeng]

1. if the direction Vector given isn't normalized, function PointRotateAroundVector get wrongs results.
2. Apparently, PointRotateAroundVector function need more computions than PointRotateAroundVector I write.
3. Q_rsqrt , Q_fabs not necessarily faster than 1.0f /sqrtf() and fabs() that std c lib provide.

https://gist.github.com/suijingfeng/92e510aafe0e0246b3b4648c2c5eac21