CRASHES
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20121129.1411: editting/moving phys object across region boundries causes crash
    getPos-> btRigidBody::upcast -> getBodyType -> BOOM
20121128.1600: mesh object not rezzing (no physics mesh).
    Causes many errors. Doesn't stop after first error with box shape.
    Eventually crashes when deleting the object.

BULLETSIM TODO LIST:
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Neb car jiggling left and right
Vehicles (Move smoothly)
Light cycle falling over when driving
Light cycle not banking
Do single prim vehicles don't seem to properly vehiclize.
Gun sending shooter flying
Collision margin (gap between physical objects lying on each other)
Boundry checking (crashes related to crossing boundry)
    Add check for border edge position for avatars and objects.
    Verify the events are created for border crossings.
Avatar rotation (check out changes to ScenePresence for physical rotation)
Avatar running (what does phys engine need to do?)
Small physical objects do not interact correctly
    Create chain of .5x.5x.1 torui and make all but top physical so to hang.
        The chain will fall apart and pairs will dance around on ground
    Chains of 1x1x.2 will stay connected but will dance.
    Chains above 2x2x.4 are move stable and get stablier as torui get larger.
Add material type linkage and input all the material property definitions.
	Skeleton classes and table are in the sources but are not filled or used.
Add PID motor for avatar movement (slow to stop, ...)
Implement function efficiency for lineaar and angular motion.

After getting off a vehicle, the root prim is phantom (can be walked through)
    Need to force a position update for the root prim after compound shape destruction
Find/remove avatar collision with ID=0.
Test avatar walking up stairs. How does compare with SL.
    Radius of the capsule affects ability to climb edges.
Tune terrain/object friction to be closer to SL.
Debounce avatar contact so legs don't keep folding up when standing.
Implement LSL physics controls. Like STATUS_ROTATE_X.
Add border extensions to terrain to help region crossings and objects leaving region.
Linkset explosion after three "rides" on Nebadon lite vehicle (LinksetConstraint)

Speed up creation of large physical linksets
	For instance, sitting in Neb's car (130 prims) takes several seconds to become physical
Performance test with lots of avatars. Can BulletSim support a thousand?
Optimize collisions in C++: only send up to the object subscribed to collisions.
    Use collision subscription and remove the collsion(A,B) and collision(B,A)
Check wheter SimMotionState needs large if statement (see TODO).

Implement 'top colliders' info.
Avatar jump
Implement meshes or just verify that they work.
Do prim hash codes work for sculpties and meshes?
Performance measurement and changes to make quicker.
Implement detailed physics stats (GetStats()).

Eliminate collisions between objects in a linkset. (LinksetConstraint)
    Have UserPointer point to struct with localID and linksetID?
    Objects in original linkset still collide with each other?

Measure performance improvement from hulls
Test not using ghost objects for volume detect implementation.
Performance of closures and delegates for taint processing
	Are there faster ways?
	Is any slowdown introduced by the existing implementation significant?
Is there are more efficient method of implementing pre and post step actions?
	See http://www.codeproject.com/Articles/29922/Weak-Events-in-C

Package Bullet source mods for Bullet internal stats output

Physics Arena central pyramid: why is one side permiable?

INTERNAL IMPROVEMENT/CLEANUP
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Remove unused fields from ShapeData (not used in API2)
Breakout code for mesh/hull/compound/native into separate BSShape* classes
    Standardize access to building and reference code.
	The skeleton classes are in the sources but are not complete or linked in.
Generalize Dynamics and PID with standardized motors.
Generalize Linkset and vehicles into PropertyManagers
    Methods for Refresh, RemoveBodyDependencies, RestoreBodyDependencies
	Possibly generalized a 'pre step action' registration.
Complete implemention of preStepActions
	Replace vehicle step call with prestep event.
	Is there a need for postStepActions? postStepTaints?
Implement linkset by setting position of children when root updated. (LinksetManual)
LinkablePrim class? Would that simplify/centralize the linkset logic?
Linkset implementation using manual prim movement.
Linkset implementation using compound shapes.
    Compound shapes will need the LocalID in the shapes and collision
    processing to get it from there.
BSScene.UpdateParameterSet() is broken. How to set params on objects?
Remove HeightmapInfo from terrain specification.
    Since C++ code does not need terrain height, this structure et al are not needed.
Add floating motor for BS_FLOATS_ON_WATER so prim and avatar will
    bob at the water level. BSPrim.PositionSanityCheck().

DONE DONE DONE DONE
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Cleanup code in BSDynamics by using motors.
Consider implementing terrain with a mesh rather than heightmap.
    Would have better and adjustable resolution.
NOTDONE: Build terrain mesh so heighmap is height of the center of the square meter.
    SL and ODE define meter square as being at one corner with one diagional.
Terrain as mesh.
How are static linksets seen by the physics engine?
    A: they are not linked in physics. When moved, all the children are repositioned.
Remember to remove BSScene.DetailLog Refresh call.
Convert BSCharacter to use all API2
Avatar pushing difficult (too heavy?)
Use asset service passed to BulletSim to get sculptie bodies, etc.
Vehicles (fix bouncing on terrain)
Remove old code in DLL (all non-API2 stuff).
Measurements of mega-physical prim performance (with graph)
Debug Bullet internal stats output (why is timing all wrong?)
	Bullet stats logging only works with a single instance of Bullet (one region).