Unwarp angles before plotting them.

[ValerioMagnago]

Jumps in the angle plot make hard to compare different trajectory. In this commit we unwrap the angles before plotting them.

Before:

After:

[MichaelGrupp]

Please don't change the default and make this an option (for the function and in the CLI or settings). I would only see this as meaningful when dealing with pure 2d rotation, but also there someone might want to see the absolute values instead.

Also note that for the purpose of rotation comparison, the rotation error metrics in RPE/APE are generally more stable than anything that is based on Euler angles.