Add Hebrew interface translation. (#2573)

* follow the instructions for registering the language as stated on the Tootsuite's docs.

* Added translation strings from latest master

Adding ‏ characters to many strings that are misdirected in the interface.

A tiny grammar fix

Updates of Hebrew strings to v1.3.1

Hebrew translation of the mailer templates.

Fix strings and a missing comma.

Just discovered two string keys were updated. this should lay Travis' mind to rest at last.

Remove mentions before counting characters to decide RTL ratio

Fixes for PR #2573

updated strings for latest master

Undo RTL counting, moved out to another branch for future consideration...

app/assets/javascripts/components/locales/index.jsx

@@ -3,6 +3,7 @@ import en from './en';
 import de from './de';
 import es from './es';
 import fa from './fa';
+import he from './he';
 import hr from './hr';
 import hu from './hu';
 import io from './io';
@@ -29,6 +30,7 @@ const locales = {
   de,
   es,
   fa,
+  he,
   hr,
   hu,
   io,