Adding readme to all the gadgets (aim to be slightly modified)

src/Common.css

src/HorizontalGauge/HozirontalGauge.js

src/InteractionTrace/InteractionTrace.js

src/LatestInteraction/RosLastestInteraction.js

src/MemoryRanked/RosMemoryRanked.js

src/Mood/RosMood.js

src/VideoStream/index.js

src/devel-2-config.js