Add link to screencast

Fix typos

Minor refactoring

Update dashboard screenshot

Add screenshots to README.md

Use faster t-SNE implementation

Add MAGIC telescope dataset

Mention all datasets in README.md

Use placeholder instead of value, such that t-SNE caching has an effect

Improve layout of dashboard

Annotate scatterplot with feature values

Improve dashboard input fields

Improve handling of non-numeric data

Add titanic dataset

Explicitly model NaN and non-numerical entries