MTC Pick and Place tutorial uses uninitialised value for grasp_frame_transform

[B-r-a-s-s]

The tutorial "Pick and Place with MoveIt Task Constructor" nicely illustrates how to use MTC. At some point, the grasp_frame_transform is set as follows:

Eigen::Isometry3d grasp_frame_transform;
Eigen::Quaterniond q = Eigen::AngleAxisd(M_PI / 2, Eigen::Vector3d::UnitX()) *
                      Eigen::AngleAxisd(M_PI / 2, Eigen::Vector3d::UnitY()) *
                      Eigen::AngleAxisd(M_PI / 2, Eigen::Vector3d::UnitZ());
grasp_frame_transform.linear() = q.matrix();
grasp_frame_transform.translation().z() = 0.1;

This worked fine for me for some time when running my own MTC task with a code block similar to the above on my device. However, suddenly when running said MTC task from a Docker container I made for it, the task consistently crashed during the planning phase. It appears this might be due to the planner using grasp_frame_transform.translation().x() and grasp_frame_transform.translation().y(), even though those are not initialised. This us fixed this by changing the above code block to the following:

Eigen::Isometry3d grasp_frame_transform = Eigen::Isometry3d::Identity();
Eigen::Quaterniond q = Eigen::AngleAxisd(M_PI / 2, Eigen::Vector3d::UnitX()) *
                      Eigen::AngleAxisd(M_PI / 2, Eigen::Vector3d::UnitY()) *
                      Eigen::AngleAxisd(M_PI / 2, Eigen::Vector3d::UnitZ());
grasp_frame_transform.linear() = q.matrix();
grasp_frame_transform.translation().z() = 0.1;

I propose for the tutorial to follow this change to ensure defined behaviour. I've opened a pull request with the above proposal.