* [Docs] Update and improve docs for Visualize and Discover
* Create a new section for default editor docs
* Fix significant terms link
* Writer changes
* Remove pages that aren't helpful to users
* More writer changes
* adding UI styles (should extract)
* adding heatmap vislib type
* adding heatmap visualization
* adding documentation
* renaming heatmap options
* fixing options issues
* fixing color selection
* fixing / adding tests
* adding more color schemas
* adding more options
* adding cell labels
* fixing selenium test
* only allow to rotate labels by 90 degrees
* converting color number slider to number input
* hide labels if they don't fit
* fixing small issues
* improved range options
* fixing based on Thomas' review
* rebasing on master and fixing linting issues
* adding selenium tests
* fixing alerts
* fixing padding
* fixing based on review
* fixing math
* fixing custom range options
* removing $timeout
* notification in case labels were hidden
* fixing tests
* fixing based on last review
* fixing based on thomas' review
