Minor fixes to steam and added new evaluators for classic preintegration

[keenan-burnett]

This PR adds a few new evaluators and super cost terms to STEAM motivated by doing lidar-inertial odometry using classic preintegration (On-Manifold Preintegration for Real-Time Visual-Inertial Odometry) and using IMU measurements to undistort a pointcloud without any continuous-time methods.

• SE3StateVarGlobalPerturb is an alternative to SE3StateVar where the stored transform is assumed to be T_i_v and perturbations are applied on the right-hand side as: C <- C * exp(delta_phi^), r <- r + C * delta_r. You need to be careful when using this variable type because other evaluators typically assume that they are being given an SE3StateVar and won't work with this one. So, for point-to-plane ICP you have to use P2PlaneErrorGlobalPerturbEvaluator together with SE3StateVarGlobalPerturb for it to work.
• SE3ErrorGlobalPerturbEvaluator : used for creating a pose prior on a SE3StateVarGlobalPerturb variable
• PreIntVelocityStateVar : a velocity variable v_vi_in_i where perturbations are v_vi_in_i <- C_iv * delta_v
• P2PGlobalSuperCostTerm : point-to-plane ICP between a query frame and a map frame, undistorts the pointcloud using the IMU measurements and propagates error Jacobians accordingly to the velocity, IMU biases.
• PreintIMUCostTerm : classic preintegration between two SE3StateVarGlobalPerturb variables.