Format code

Just checked an idea for "format only the selected code" in my environment.
At the end it is extremly easy to implement.
Should be similiar for prettier

	var code = Espruino.Core.EditorJavaScript.getCode()­;
	var selected = Espruino.Core.EditorJavaScript.getSelect­edCode();
	if(selected) code = code.replace(selected,js_beautify(select­ed,options) + "\n"); //had to add linefeed for beautify, don't know wether prettier  needs this
	else code = js_beautify(code,options);
	Espruino.Core.EditorJavaScript.setCode(c­ode);