fixed typo in editor.html

src/editor.html

 		<!-- ZSSRichTextEditor Editable Content -->
 		<div id="zss_editor_title" class="zss_editor_title" contenteditable="true" placeholder="" disableLineBreaks="true"></div>
 		<div id="separatorContainer"><hr></div>
-		<div id="zss_editor_content" class="zs_editor_content" contenteditable="true" placeholder=""></div>
+		<div id="zss_editor_content" class="zss_editor_content" contenteditable="true" placeholder=""></div>
 		<div id="zss_editor_footer"></div>
 	</body>
-</html>
+</html>