Constraints and bhkPoseArray update

1. Added compound "ConstraintBasicData" because this sequence of basic data appears in every havok constraint. **This change cause that Nifskope don't render any havok constraint. If this change in nif.xml will be approved, it would require to update Nifskope code.**
2. bhkRDTConstraint renamed to RDTConstraint and unified its structure to use standard constraint descriptors.
3. Added description for bhkPoseArray (used in Fallout3 .psa files).
4. Added description for bhkBallAndSocketConstraint.
5. Added description for bhkBallSocketConstraintChain. Description of *Tau*, *Damping*, *CFM* and *Max Error Distance* based on source code [here](https://github.com/projectanarchy/projectanarchy/blob/master/Source/Physics2012/Dynamics/Constraint/Chain/BallSocket/hkpBallSocketChainData.h) and [here](https://github.com/projectanarchy/projectanarchy/blob/master/Source/Physics2012/Dynamics/World/hkpWorldCinfo.h).
6. Update description for bhkBreakableConstraint.
7. Changed order of bhkConstraint related blocks to be on one place.