v1.4.0

New features

• The errors argument in transformErrors now have a schemaPath (#1205). Fixes #838 and #818.
• Basic support for nullable types (#1213). This is a targeted fix that allows "type": [<T>, "null"] to be interpreted as "type": <T>.
• No longer throw an error, but log a warning instead, when properties in ui:order do not correspond to any property in the schema (#814).

Bug fixes

• Use plain text in playground demos (#1215).
• Reduce number of "empty" meaningless divs (#1218).
• Don't try to "merge" Files (#1234).
• Documentation - no longer pass a schema attribute when rendering HTML (#946).
• Document placeholder and autofocus widget props (#1223).
• Add the Mozilla Code of Conduct (#1240).