first working version. need to improve styling (right align for number cells)

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/Components/MarkdownEditor.svelte

@@ -138,7 +138,7 @@
     <span id="restore_markdown" onclick={restore} class="hint">{t('unsaved_content')}</span>
     {/if}
     <textarea bind:value={editValue.source} onkeyup={typed} autofocus={!simple}></textarea>
-    <Display classes="preview" markdown={editValue} />
+    <Display classes="preview" bind:markdown={editValue} />
     {#if !simple}
     <div class="buttons">
         <button class="cancel" onclick={e => editing = false}>{t('cancel')}</button>