Text to Speech (#2)

* Initial TTS scrapping implemented

* Audio & copy buttons added

* TTS langs mapping fix

* Webkit audio api fix

* Added TTS-related testing

* Last tweaks

utils/languages.json

@@ -123,7 +123,8 @@
     "source": {},
     "target": {
       "zh": "zh-CN",
-      "zh_HANT": "zh-TW"
+      "zh_HANT": "zh-TW",
+      "auto": "en"
     }
   }
 }