Optimize _phDdvtUpdateChild.
No need for _phDdvtUpdateLeaf.
Optimize _phDdvtNextChild, _phDdvtPairNext
Optimize particle collision acknowledging
Optimize phListNext
Inline part of ddvtpair iteration and deref in world step.
Inline checking first in nextCollisions.
Don't update if lt 1/10th away from position in ddvt
Disable shared lib. Use -O4 in link flags.
Optimize phAppend, phRemove
Optimize phIterate.
Store top fully encompassing ddvt of a particle.

Optimizes lookup of ddvts to update for a particle.
Embed world data in particle.
Add phShift.
Use phShift in world collision list work.
Deref world ddvtpair leaf iterators and particle a.
Use formal test pair loop.
Reconfigure example for ph-stress app.
Benchmark an alternative phIntersect
Replace list iteration with array iteration in ddvtpair