New feature: Euler-Bernoulli beams can have nodes rotated in whatever direction, then one can use SetNodeAreferenceRot() and SetNodeBreferenceRot() to change the initial 'reference' rotation of nodes respect to the reference of the beam.
Also, the ChMatrixCorotation class has been made more general.
Merge branch 'develop' of https://github.com/projectchrono/chrono into develop