Add <bdi> tags around text fields.
Add Farsi and Arabic translations
Update dir attribute depending on the language.
Merge remote-tracking branch 'origin/lucyhe-polymer_ui_for_copypaste' into lucyhe-add_arabic_translation

Conflicts:
	src/samples/copypaste-socks-chromeapp/getter.html
	src/samples/copypaste-socks-chromeapp/getter.ts
	src/samples/copypaste-socks-chromeapp/giver.html
	src/samples/copypaste-socks-chromeapp/giver.ts
	src/samples/copypaste-socks-chromeapp/root.ts
Small style fixes + comments.
Translate text only as necessary.

i.e. instead of translating the entire app when a new element is added,
only translate the text within the new element.
Also, store messages.json locally so that it is only fetched when the
language is changed.
Merge remote-tracking branch 'origin/dev' into lucyhe-add_arabic_translation
Rename function that adds translated text
Merge pull request #147 from uProxy/lucyhe-add_arabic_translation

Support bidirectional text, add Arabic & Farsi translations