Sensor models: one for each combination of {landmark_parameterization,observation_type}

Classes
struct	srba::sensor_model< landmarks::Euclidean3D, observations::MonocularCamera >
struct	srba::sensor_model< landmarks::Euclidean3D, observations::StereoCamera >
struct	srba::sensor_model< landmarks::Euclidean3D, observations::Cartesian_3D >
struct	srba::sensor_model< landmarks::Euclidean2D, observations::Cartesian_2D >
struct	srba::sensor_model< landmarks::Euclidean3D, observations::RangeBearing_3D >
struct	srba::sensor_model< landmarks::Euclidean2D, observations::RangeBearing_2D >
struct	srba::sensor_model< landmarks::RelativePoses2D, observations::RelativePoses_2D >
struct	srba::sensor_model< landmarks::RelativePoses3D, observations::RelativePoses_3D >