Use enums instead of bool for some configuration options
In particular, StateBlocks have two options: fixed/unfixed, and transformable/non_transformable
I propose to create enums for this, so that the constructors can be read by humans:
from
auto sb = StatePoint3d(Vector3d::Zero(), true, true);
to
auto sb = StatePoint3d(Vector3d::Zero(), SB_FIXED, SB_TRANSFORMABLE);