text box style.

demo clean up.
rearranged demo.

add TextBox.
添加icon支持。
整理了textbox样式。
fix comments on check in.
Merge branch '3.1.0-dev' of https://github.com/ecomfe/esui into 3.1.0-dev
fixed comments.
rollback a demo change in classic textbox.html.
Merge pull request #361 from yankun01/3.1.0-dev

添加Textbox的代码