* added arabic language locale file

* complete the missing transaltion and fixed a typo

* Pagination:fix IE onchange doesn't work Bug

Pagination:fix IE onchange doesn't work Bug

* Update pagination.js

* Update pagination.js

* 	add accessibility for Alert、Button、 Breadcrumb、 Checkbox

* Update checkbox.md

* Update DateTimePicker doc

* Update Tree doc

* Update DateTimePicker doc

* Update Tree doc

* update doc

* Update datetime-picker.md

* ColorPicker: support user input

* support alpha

* Update picker-dropdown.vue

* DateTimePicker: add timeformat for datetimerange

* fix

* DatePicker: fix picker interaction

* DatePicker: fix picker interaction

* fix

* DatePicker: fix picker interaction

Input-Number: fixed multi-size component border overflow, tested on chrome 60, canary, chromium, safari, firefox (#6310)