Add a server side workaround for #674 to support NuGet 2.1 client.
Fix the gallery not to spam people with 'your email address changed' messages by sending to users with unconfirmed email addresses or by email in response to requests that include an invalid challenge token.
Merge branch 'confirmationemail' into Preview
Fix newly introduced null reference exception caught by unit tests.
Merge branch 'Fix674' into Preview