Editor should download the latest schema automatically

Currently you need to download the latest schema manually, select it in Preferences and enable schema validation.

Suggestion would be (as in Alces) to download the latest schema version at startup and use it by default during validation. Still need a way to select a different one (like for private namespaces) using a browser. And go back to the latest one easily (popup), and maybe select an older version of the schema. Since backwards compatible maybe not really needed. No need to download all?

Ideally, during validation, the JDF Version of the JDF is used to select the matching schema to validate (auto mode).