Multiply this quaternion by <code>q</code>.
<p>
If <code>T</code> is <code>this</code> and <code>Q</code> is the given
quaternion, then the resulting quaternion <code>R</code> is:
<p>
<code>R = T * Q</code>
<p>
So, this method uses post-multiplication like the matrix classes, resulting in a
vector to be transformed by <code>Q</code> first, and then by <code>T</code>.
@param q
the quaternion to multiply <code>this</code> by
@return this
Multiply this quaternion by <code>q</code>. <p> If <code>T</code> is <code>this</code> and <code>Q</code> is the given quaternion, then the resulting quaternion <code>R</code> is: <p> <code>R = T * Q</code> <p> So, this method uses post-multiplication like the matrix classes, resulting in a vector to be transformed by <code>Q</code> first, and then by <code>T</code>.
@param q the quaternion to multiply <code>this</code> by @return this