Clears the status {@link #text} and {@link #iconCls}. Also supports clearing via an optional fade out animation.

@param {Object} [config] A config object containing any or all of the following properties.  If this
object is not specified the status will be cleared using the defaults below:
@param {Boolean} config.anim True to clear the status by fading out the status element (defaults
to false which clears immediately).
@param {Boolean} config.useDefaults True to reset the text and icon using {@link #defaultText} and
{@link #defaultIconCls} (defaults to false which sets the text to '' and removes any existing icon class).

@return {Ext.ux.statusbar.StatusBar} this
function(o) {
        o = o || {};

        var me = this,
            statusEl = me.statusEl;

        if (o.threadId && o.threadId !== me.activeThreadId) {
            // this means the current call was made internally, but a newer
            // thread has set a message since this call was deferred.  Since
            // we don't want to overwrite a newer message just ignore.
            return me;
        }

        var text = o.useDefaults ? me.defaultText : me.emptyText,
            iconCls = o.useDefaults ? (me.defaultIconCls ? me.defaultIconCls : '') : '';

        if (o.anim) {
            // animate the statusEl Ext.Element
            statusEl.el.puff({
                remove: false,
                useDisplay: true,
                callback: function() {
                    statusEl.el.show();
                    me.setStatus({
                        text: text,
                        iconCls: iconCls
                    });
                }
            });
        } else {
             me.setStatus({
                 text: text,
                 iconCls: iconCls
             });
        }
        return me;
    }