Little improvement on the readmes of each widget

public/LearnMore.css

public/light-flat.css

src/Common.css

src/HorizontalGauge/HozirontalGauge.js

src/InteractionTrace/InteractionTrace.js

src/LatestInteraction/RosLastestInteraction.js

src/LatestInteraction/index.js

src/LineChart/RosLineChart.js

src/MemoryRanked/MemoryRanked.js

src/MemoryRanked/RosMemoryRanked.js

src/Mood/Mood.js

src/Mood/RosMood.js

src/VideoStream/index.js

src/index.js