Compute the difference between <code>this</code> and the <code>other</code> quaternion
and store the result in <code>this</code>.
<p>
The difference is the rotation that has to be applied to get from
<code>this</code> rotation to <code>other</code>. If <code>T</code> is <code>this</code>, <code>Q</code>
is <code>other</code> and <code>D</code> is the computed difference, then the following equation holds:
<p>
<code>T * D = Q</code>
<p>
It is defined as: <code>D = T^-1 * Q</code>, where <code>T^-1</code> denotes the {@link #invert() inverse} of <code>T</code>.
Compute the difference between <code>this</code> and the <code>other</code> quaternion and store the result in <code>this</code>. <p> The difference is the rotation that has to be applied to get from <code>this</code> rotation to <code>other</code>. If <code>T</code> is <code>this</code>, <code>Q</code> is <code>other</code> and <code>D</code> is the computed difference, then the following equation holds: <p> <code>T * D = Q</code> <p> It is defined as: <code>D = T^-1 * Q</code>, where <code>T^-1</code> denotes the {@link #invert() inverse} of <code>T</code>.
@param other the other quaternion @return this