Merge branch 'issue-3' into 'develop-v2.1.1'

diagrams/SAREF4GRID examples.xml

diagrams/SAREF4GRID figures.xml

documentation/diagrams/SAREF4GRID_Action_service.png

documentation/diagrams/SAREF4GRID_Activity_calendar.png

documentation/diagrams/SAREF4GRID_Breaker_state.png

documentation/diagrams/SAREF4GRID_Clock.png

documentation/diagrams/SAREF4GRID_Electric_grid_meter.png

...ation/diagrams/SAREF4GRID_Energy_and_power_properties.png

documentation/diagrams/SAREF4GRID_Example_action_1.png

documentation/diagrams/SAREF4GRID_Example_action_2.png

documentation/diagrams/SAREF4GRID_Example_action_3.png

...ntation/diagrams/SAREF4GRID_Example_activity_calendar.png

documentation/diagrams/SAREF4GRID_Example_breaker_state.png

documentation/diagrams/SAREF4GRID_Example_clock.png

documentation/diagrams/SAREF4GRID_Example_firmware.png

documentation/diagrams/SAREF4GRID_Example_get_1.png

documentation/diagrams/SAREF4GRID_Example_get_2.png

documentation/diagrams/SAREF4GRID_Example_get_3.png

documentation/diagrams/SAREF4GRID_Example_get_4.png

documentation/diagrams/SAREF4GRID_Example_get_5.png