Added email verification for users

The verification email is sent if needed when profile is updated (either when the email is changed from the previous time or it was an old account and didn't have the token value)

You can test it here: http://verify.gae-init.appspot.com/profile/

![screen shot 2014-08-14 at 19 46 25](https://cloud.githubusercontent.com/assets/125676/3924464/a9cb5d1e-23dd-11e4-9c63-54d00363f42c.png)
:+1:

```python
'''Hello %(name)s,

it seems someone (hopefully you) tried to verify this email address with %(brand)s.

In case it was you, please verify your email by following this link:
%(link)s

If it wasn't you, we apologize. Please do _not_ click on the above link so your email won't be verified.
You can either ignore this email or reply to it so we can take a look.

Best regards,
%(brand)s
'''
```