[FEATURE] Live preview of rendered markdown (not MD Extra) in editor elements. Preview will
be shown below the textarea field and updated via keyup event. The preview box can be
resized by clicking on it, 2nd click puts it back to default height. Hidden Live-Scrolling
feature: If you scroll to position x in the preview box and you edit the same position in the
textarea you will have the preview box updated with your current text without scrolling.
[FEATURE] Markdown Extra can be enabled or disabled only for transactional emails.
Add interface SchumacherFM_Markdown_Model_Markdown_Interface if you want to
implement your own MD parser.