Cleanup

Update to ckeditor v4.21.0 full

Host a local copy of CKEditor 4.21 full all

Remove magickline paragraph break

Update README.md

Add doNotRender method to BaseModel

Fix function_exists phpb_registered_assets

Set 404 headers

Refactor

Fix setLanguage, check whether keys are valid languages (renderPageBu…

…ilderBlock uses pageData without language data)