Added readme for i18n

i18n.md

+Blink Translations (i18n)
+=========================
+
+Translate
+---------
+
+Blink translations should be made using the 'Qt Linguist' program.
+
+You need to open `resources/i18n/blink__LANGUAGE_CODE__.ts` and translate the text.
+
+After you're done, save the file and run `release_translations`.
+
+
+Update translation files
+------------------------
+
+To update the translation files with the newly added text if the application changed you need to run:
+`generate_translations`
+
+
+Adding a language
+-----------------
+
+If you want to add a language to Blink, you need to change `blink-qt.pro` and add the language in the `TRANLATIONS` line.
+
+The format needs to be `resources/i18n/blink_LANGUAGECODE_.ts`.
+
+After this, edit `blink/preferences.py` and add the name of the language to the mapping:
+
+```python
+    mapping = {"default": "System default",
+               "en": "English",
+               "nl": "Nederlands",
+               "ro": "Română"}
+```
+
+After this you can run `generate_translations` and proceed to translate the newly generated file.
+