added experimental live-editing features
changelog
notifying about changes + explaining how to revert them
added column.indexOf + dataset.indexOf()
enabled live-editing in line and bar chart too
exitting live edit using esc and enter
added test for new dataset.api
added dataset.reset()
changelog
resetting dataset as new visualizations are loaded
Merge branch 'feature/live-editing' into develop
Merge branch 'develop' of github.com:datawrapper/datawrapper into develop