Robot InsertWaypointPre/es

Description
Inserts a waypoint from preselected objects into a trajectory.

Usage
Depending on the used navigation style preselecting may vary.
 * For example, when using Blender navigation, you can hover with the mouse cursor over an object to highlight (preselect) it.
 * Make sure, a trajectory is selected in the Tree view.
 * Press to insert this waypoint into the selected trajectory.