• ElContainer, imported in prelude, renamed to View. (Breaking)
• Internal refactor of El: Now wrapped in Node, along with
  Empty and Text. Creation macros return Node(Element). (Breaking)
• Changed the way special attributes like disabled, autofocus, and
  checked are handled (Breaking)
• MessageMapper now accepts closures
• Orders is a trait now instead of a struct. (Breaking)
• Significant changes to MessageMapper
• Orders has new methods, clone_app and msg_mapper which can allow access to app instance.
• Added more SVG element macros
• Several minor bux fixes
• Examples updated to reflect these changes
• Improvements to Fetch API, especially regarding error handling
  and deserialization