ENH: improve, simplify, rationalize coordinate system handling (issue #863)
Previously the coordinate system functionality was split between coordinateSystem and coordinateRotation. The coordinateRotation stored the rotation tensor and handled all tensor transformations. The functionality has now been revised and consolidated into the coordinateSystem classes. The sole purpose of coordinateRotation is now just to provide a selectable mechanism of how to define the rotation tensor (eg, axis-angle, euler angles, local axes) for user input, but after providing the appropriate rotation tensor it has no further influence on the transformations. -- The coordinateSystem class now contains an origin and a base rotation tensor directly and various transformation methods. - The origin represents the "shift" for a local coordinate system. - The base rotation tensor represents the "tilt" or orientation of the local coordinate system in general (eg, for mapping positions), but may require position-dep...