function setButtonText(text) {
				var $span = $('span.' + textCls, self.getEl());

				if (text) {
					if (!$span[0]) {
						$('button:first', self.getEl()).append('<span class="' + textCls + '"></span>');
						$span = $('span.' + textCls, self.getEl());
					}

					$span.html(self.encode(text));
				} else {
					$span.remove();
				}

				self.classes.toggle('btn-has-text', !!text);
			}
Renders the control as a HTML string.

@method renderHtml
@return {String} HTML representing the control.