Add support for readonly attribute on textarea

src/js/easymde.js

@@ -2121,6 +2121,7 @@ EasyMDE.prototype.render = function (el) {
         lineWrapping: (options.lineWrapping === false) ? false : true,
         allowDropFileTypes: ['text/plain'],
         placeholder: options.placeholder || el.getAttribute('placeholder') || '',
+        readOnly: el.readOnly,
         styleSelectedText: (options.styleSelectedText != undefined) ? options.styleSelectedText : !isMobile(),
         scrollbarStyle: (options.scrollbarStyle != undefined) ? options.scrollbarStyle : 'native',
         configureMouse: configureMouse,