* [DatePicker] Added the possibilitie to pass custom prefix and suffix icon class with same props as usual (prefix-icon and suffix-icon)

* [DatePicker] Fixed error in previous commit and updated english documentation according to icon changes

* Renamed suffix-icon to clear-icon, and updated english doc

* Cleaned unnecessary lines

* expand filter-method param

* update table.md

* fix show loading, leak memory

* $on -> $once

* refresh Trv

* remove space

- Files: README.md
- Changes: 
    * License File Linked
    * License Badge Added

* add cascader blur & focus event

* fix 'Input Events' => 'Cascader Events'

overload validate method
add clearValidate method

* spread -> merge

* Update table-store.js

* Added example that exposes the issue

* Fixed issue if select component has collapse tags and filtering enabled at the same time

* tests

* simpler tests

* chore: update ESLint

* chore: update eslint ignore

* Form: fix async validate bug

* Form: fix async validate bug

* When dialo's <appendToBody> is true, remove DOM node after destory

* el-submenu add show-timeout,hide-timeout attributes

* el-submenu add show-timeout,hide-timeout attributes

* el-submenu add show-timeout,hide-timeout attributes

* add the definition for SubMenu

* Table: remove condition due to rows has been accessed prior

* Table: change el-tooltip style to object
Signed-off-by: Clark Du <clark.duxin@gmail.com>