move the required-mark on right

Move the required-mark on the right side of the input-field, and make it more semantic, easily style it with css. 

Then the label can right-align, make it close to the input field.

![selection_004](https://f.cloud.github.com/assets/330812/1681032/72edb2f2-5d8a-11e3-97da-24fdd9710d22.png)