One column in the joint bars cause some problems to layout

[torydebra]

Hi, I am using your GUI, and noticed a thing. When joints are less than 8, one column is used (ca51808).
Have you tested this thing? On my "fork" the result is this:

By the way, I am not sure if this is caused by my modifications, or it is a problem that also robot_monitoring has

[torydebra]

Returning to this after ages, just a thing that can improve the visualization and save space if joints are only a few: in the bar_plot_widget

robot_monitoring/src/joint_state_gui/bar_plot_widget.cpp

Line 76 in 0e24908

could be useful to remove the columns if they are empty:

  //remove layout if it is empty to handle better the space
  if (bars_layout_center->count() == 0) {
      bars_layout_center->setParent(nullptr);
      auto line = findChild<QWidget *>("line_2");
      line->setVisible(false);
  }
  if (bars_layout_right->count() == 0) {
      bars_layout_right->setParent(nullptr);
      auto line = findChild<QWidget *>("line");
      line->setVisible(false);
  }

@alaurenzi