Fixed crv2rotation

[ben-l-p]

Found a bug in the conversion from a $\boldsymbol{\Psi}$ vector to a rotation matrix $\mathbf{R}$. This only applies for larger $\Psi$ angles, as the small angle correction (which most "normal" cases will use) is correct.

Intended expression:
$$\mathbf{R} = \mathbf{I} + \sin||{\boldsymbol{\Psi}||} \tilde{\boldsymbol{\Psi}} + \frac{1-\cos{||\boldsymbol{\Psi}||}}{||\boldsymbol{\Psi}||^2}\tilde{\boldsymbol{\Psi}} \tilde{\boldsymbol{\Psi}}$$

Used expression:
$$\mathbf{R} = \mathbf{I} + \frac{\sin||\boldsymbol{\Psi}||}{||\boldsymbol{\Psi}||} \tilde{\boldsymbol{\Psi}} + (1-\cos{||\boldsymbol{\Psi}||})\tilde{\boldsymbol{\Psi}} \tilde{\boldsymbol{\Psi}}$$

[kccwing]

Thanks @ben-l-p! Note line 561 normalises the vector - then referring to eq C10 in Dynamics of Flexible Aircraft - the existing expression seems to be correct.

[ben-l-p]

I'm bad at maths, back to the drawing board...