Affine3f/Affine3d classes

Adding stack allocated Affine3f class that can represent a camera, an arbitrary object or a coordinate frame pose. It's useful for any code connected with odometry, object scanning, sfm, etc. It was designed in Eigen::Affine3f style.

Before the class, users had to use heap allocated Mat, keep history of rotations and translations in separate std::vectors, pass two parameter to functions. Or, as alternative, use sub matrices for combining/extracting  R and t to /from single 4x4 matrix. All this led to less convenient and littered code.