fix ComputeIk() call for TranslationDirection5D

The ComputeIk() doc in ikfast.h says:
- ``eetrans`` - 3 translation values. For iktype **TranslationXYOrientation3D**, the z-axis is the orientation.
- ``eerot``
- For **Transform6D** it is 9 values for the 3x3 rotation matrix.
- For **Direction3D**, **Ray4D**, and **TranslationDirection5D**, the first 3 values represent the target direction.
- For **TranslationXAxisAngle4D**, **TranslationYAxisAngle4D**, and **TranslationZAxisAngle4D** the first value represents the angle.
- For **TranslationLocalGlobal6D**, the diagonal elements ([0],[4],[8]) are the local translation inside the end effector coordinate system.

Changed from Transform6D format (rotation matrix) to target direction
(TranslationDirection5D).