Euler Viewer

The application euler allows to inspect Euler angles and quaternions of rotations. It displays a simple interactive marker in rviz (on topic: /euler/updates).

1. Inspect the commits to learn about creating interactive rviz markers and interconnecting them to the app.
2. Augment the marker display with a frame (composed from three arrows).
3. Modify the MainWindow class to update the orientation of frame1+2 (adding Euler angles) and frame1*2 (correctly composing orientations by quaternion multiplication).
4. Analyse when orientations of frame1+2 and frame1*2 are identical.
5. Implement Quaternion slerp to perform interpolation between frame1 and frame2. To this end, clone and modify main.cpp and MainWindow, such that only two RotationControl instances are used. The interpolation should be performed continously, e.g. using a QThread.
6. Create a copy of main.cpp and MainWindow to display the same orientation with two different Euler angles. Interlink the corresponding instances of RotationControl.