Add Arabic README and CONTRIBUTING (#404)

* Add Arabic translation for README and CONTRIBUTING

* Move Arabic to alphabetical location in CONTRIBUTING

* Update CONTRIBUTING.ko_kr.md

* Update CONTRIBUTING.md

* Update README.zh_tw.md

* Update README.zh_cn.md

* Update README.zh_cn.md

* Update README.ru.md

* Update README.pt_br.md

* Update README.md

* Update README.ko_kr.md

* Update README.it.md

* Update README.id.md

* Update README.hi_in.md

* Update README.fr.md

* Update README.es.md

* Update README.de.md

* Update README.ar.md

* Update README.zh_tw.md

README.md

@@ -10,13 +10,14 @@
 [Français][FR],
 [Italiano][IT],
 [Português][PT_BR],
+[Русский][RU],
+[العربية][AR],
+[हिंदी][HI_IN],
 [正體中文][ZH_TW],
 [简体中文][ZH_CN],
-[한국어][KO_KR],
-[हिंदी][HI_IN],
-[Русский][RU]
-
+[한국어][KO_KR]
 
+[AR]:README.ar.md
 [ID]:README.id.md
 [CA]:README.ca.md
 [DE]:README.de.md