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/views/user_mailer/confirmation_instructions.he.html.erb

@@ -0,0 +1,14 @@
+<div lang="he" dir="rtl">
+<p>שלום <%= @resource.email %> !</p>
+
+<p>הרגע יצרת חשבון בקהילה <%= @instance %>.</p>
+
+<p>כדי לוודא את הרשמתך, יש ללחוץ על הקישורית הבאה : <br>
+<%= link_to 'Confirm my account', confirmation_url(@resource, confirmation_token: @token) %>
+
+<p>יש לעבור גם על תנאי השימוש <%= link_to 'terms and conditions', terms_url %>.</p>
+
+<p>בתודה מראש,<p>
+
+<p>צות ניהול <%= @instance %></p>
+</div>