Merge branch 'master' into feature/end-effector-trajectories

source/RobotAPI/libraries/skills_gui/SkillMemoryGui.cpp

source/RobotAPI/libraries/skills_gui/SkillMemoryGui.h

...raries/skills_gui/executions/SkillExecutionTreeWidget.cpp

...ibraries/skills_gui/executions/SkillExecutionTreeWidget.h

...otAPI/libraries/skills_gui/memory/SkillManagerWrapper.cpp

...obotAPI/libraries/skills_gui/memory/SkillManagerWrapper.h

...braries/skills_gui/skill_details/SkillDetailsGroupBox.cpp

...libraries/skills_gui/skill_details/SkillDetailsGroupBox.h

...aries/skills_gui/skill_details/SkillDetailsTreeWidget.cpp

...ce/RobotAPI/libraries/skills_gui/skills/SkillGroupBox.cpp

source/RobotAPI/libraries/skills_gui/skills/SkillGroupBox.h

.../RobotAPI/libraries/skills_gui/skills/SkillTreeWidget.cpp

...ce/RobotAPI/libraries/skills_gui/skills/SkillTreeWidget.h