Update README.rst

On an existing project, the SITE_ID information in settings.py is missing from the doc. If we follow step by step the documentation, there is an error when we try to reach the admin pages
Fixed last_name key.
Merge pull request #522 from guillaumevincent/patch-1

Add SITE_ID information missing in settings.py
Merge pull request #533 from ldgarcia/master

Paypal provider: Fixed last_name key in extract_common_fields.
Merge pull request #534 from replay/master

added a new option LOGIN_ON_EMAIL_CONFIRMATION
Added pip install to README
fix french translation

missing 'minimum' information in french translation for "Password must be a minimum of {0} characters."
Merge pull request #536 from guillaumevincent/patch-2

fix french translation
Custom signup form `save` renamed to `signup` (closes #528)
Added hopper.pw
Moving login to the adapter (closes #519)
OpenID does not respect next/process (closes #473)
Properly handle case insensitive e-mail (closes #517)
Squashed commit of the following:

commit fefd63b9fe64f50f28bac962d773ed35a9170b8f
Author: replay <mauro.stettler@gmail.com>
Date:   Wed Feb 12 19:28:04 2014 +0300

    add request into the params of confirm_email method

    Conflicts:
    	allauth/account/adapter.py

commit bb2ab358d91cf56c132d0aa0572bcd0ebad929be
Author: replay <mauro.stettler@gmail.com>
Date:   Wed Feb 12 18:38:42 2014 +0300

    move email confirmation from model into adapter

    Conflicts:
    	allauth/account/adapter.py
add doc for signals email_confirmed and email_confirmation_sent (closes #537)
merging from upstream