[Widgets] Add list widgets

[wuyongfeng]

1: Rich list widget, new splitbuttons, thumbnails and icons, and the widget has been initialized, and enhance the user experience.
2:Complete the simple unorderedlist single category, the button text icon and Thumbnails list view.
3:Complete the simple unorderedlist split category, the simple, text, icon, Thumbnails list view.
4:Modify the svg picture 

[zhizhangchen]

Shouldn't it inherit from SimpleList or ListBase?

[wuyongfeng]

Corrected comment requirements

[zhizhangchen]

All “Thumbnails" should be replaced with "Thumbnail"

[wuyongfeng]

Corrected comment requirements

[zhizhangchen]

Replaced by #274