* Remove span.ant-tag-text
Warp React.ReactNode with span element is not suggested. It may cause anti-specification problem: `<span><span>I'm spec breaker</span></span>`. span is not a general tags container.
Another benefit from this change is keeping the same structure with CheckableTag.
After inspecting the removing of the style of .ant-tag-text, seems bringing no problems. The old example employeed this css class has gone long long time ago. See: 0635877a51
* Use React.Children.only api to supress type casting
By codes, the children and the overlay of Dropdown must be **single** and **valid React.ReactElement**. React.Children.only takes it and report more friendly React internal built error messages.
* Revert hack CSS styles: filling .ant-tag's block area with orphan child anchor
* remove unnecessary computed props for classNames
* rollback autocomplete optimization for possible css style order issue
* update snapshots
* remove more unnecessary computed props at Input
Use ES7 style class members for event handlers so that 'this' is
automatically bound and each definition site doesn't need to manually
invoke 'bind'.
This makes all existing ES2015 class usages in components use the
same mechanism for binding.
Where necessary, prefix the classes imported from react-component
with 'Rc' rather than prefixing the Ant classes with 'Ant'.
The prefixing of Ant classes wasn't consistent and isn't necessary
in many cases.