Minor Release 0.2.0

Added functionality:

1. Adjoint matrix calculations - used to transform spatial vectors between body and world coordinate frames.
2. Functions pointAcc() and pointVel() to BModel - calculate acceleration or velocity at a point on a body.
3. Functions update_X_base and update_velocity to BDynamics - update a model's internal parameters.

Replaced some glm:: functions with equivalent arb:: functions - should improve portability.