* Refactor to extract ExpressionField
* Move styling of expression and result prefixes to CSS
* Layout expression field with grid
* Add buttons to expression field
* Enter edit mode and cancel
* Hook up editing in textarea
* Allow existing expression to be edited
* Make expression param optional
* Use ExpressionField to add new expression
* Hide cancel button if no callback and add updateLabel prop
* Only show error when dirty
* Placeholder for expression field
* Format result in expression field
* Expression field textarea styling
* Justify expressions at bottom
* Prevent jumping when editing expression
* Revert changes on cancel
* Remove unused CSS
* Extract ExpressionTextArea
* Extract ExpressionResult
* Auto height textarea
* Hover styling for expression
* Result type tag
* Tweak styling
* Update padding in expression field
* Changelog
* Enable scrolling of result when editing expression
* Use smaller close icon
* Fix enabling of add/edit button
* Focus text area when clicking edit button
* Put cursor at the end of text area when focusing it
* Enter edit mode when clicking on text area
* Remove expression in list
* Don't style expressions list as a flex box
* Show full result while editing expression
Matt Sherman