Completed conversion to UKF, functional output.
Added linear velocity y.  Duplicated PR2 robot_pose_ekf results.
A bit of cleanup.
Fixed PR2 Odometry.
Added more parameters.
Added support for delta_pose in Odometry and delta_orientation in Imu for devices that may not output velocity estimates in these messages.
Enforced timeout values
Experimental first pass at attitude filter.
Updated attitude filter, mostly works, pretty neat demo.
Added diagonal vector configuration for initial_covariance and process_noise
Fixed potential issue with gravity.
Merge pull request #9 from chadrockey/ukf

Merge ukf into main branch