• Adds view files to Gutenberg tester
• Renames editor files from jetpack-editor.* to editor.*
• Add support for RTL CSS files

Testing instructions:

• Switch to try/stylish-hello-dolly branch in Calypso (Gutenberg: add styles to Hello Dolly wp-calypso#27241)

• From calypso folder, generate files — note to change output-dir to correct place:

  npm run sdk -- gutenberg \
    --editor-script=client/gutenberg/extensions/presets/jetpack/editor.js \
    --view-script=client/gutenberg/extensions/presets/jetpack/view.js \
    --output-editor-file=editor \
    --output-view-file=view \
    --output-dir=/absolute_path_to_your_jetpack/_inc/blocks

• Add these filters to your Jetpack setup, e.g. to a file in mu-plugins folder:

  add_filter( 'jetpack_gutenberg', '__return_true' );

  These will: enable loading these Gutenberg assets from the CDN. You should see all the files throw 404. We'll still need tofollow up and add these files.

• To disable loading via CDN and load files from your local disk instead, add:

  add_filter( 'jetpack_gutenberg_cdn', '__return_false' );

  You should now see all the files load and "Hello Dolly" Gutenberg block be available:
  

• If you switch your site to RTL mode (e.g. with rtl-tester e.g. by changing your language from settings to Hebrew. RTL tester doesn't seem to trigger is_rtl()), you should see at both theme, and the editor side RTL CSS files loaded instead.