Updated math types
Update some of the math types:
- rw/math/Line2DPolar and rw/math/Vector2D
- added missing const
- rw/math/Transform2D
- Fixed documentation
- Added missing comparison operators
- Added missing boost serialization
- rw/math/Rotation2D
- Fixed documentation
- Updated Eigen type to return rotation 2D instead of matrix
- Added missing boost serialization