RHSRWAIDotSC

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   Right-hand-side of the spacecraft dynamical equations. 
   This function includes position, orientation 
   and 4 reaction wheels. It also includes time varying inertia.
   This simulation is primarily to analyze control during deployment.
   Several f
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   Inputs
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   x           (:,1)     State vector  
   t           ( 1,1)    Time
   sim         ( 1,1)    Data structure for the simulation
                         .uRWA     (3,4) Reaction wheel unit vectors
                         .tRWA     (4,1) Reaction wheel torque
                         .funIandD (1,:) Disturbance and inertia model
                         .tExt     (3,1) Other external torques

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   Outputs
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   xDot        (:,1)     State vector derivative

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