*update to v0.4.2a
1.remove $.tag, change $.tag to _.tag, so no more extra funtion attach on
jQuery
2.bar.log() will stringfy the array and object
3.add option bar_click and msg_click. so it allow to set click event on
the bar.
1.more test case
2.helpberbar add shadow
3.fix the menu column jumping issue.
1.add more test case
1.add more comments
*update to 0.4.2b
1.more comment
1.more test case
*update to 0.4.2
1. more comment.