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   Compute ECI to body quaternion from ECI position and Euler angles.
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   Form:
   qECIToB = QECI( r, e )
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   Inputs
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   r           (3,1) ECI Position vector
   e           (3,1) Euler angles [phi;theta;psi]

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   Outputs
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   qECIToB     (4,1) Quaternion from ECI to B

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