Change all Quay.io references to Quay, fix tour and change logo

Fixes #741

util/invoice.tmpl

@@ -3,10 +3,10 @@
    <table width="100%" style="max-width: 640px">
      <tr>
        <td valign="center" style="padding: 10px;">
-         <img src="https://quay.io/static/img/quay-logo.png" alt="Quay.io" style="width: 100px;">
+         <img src="https://quay.io/static/img/quay-logo.png" alt="Quay" style="width: 100px;">
        </td>
        <td valign="center">
-         <h3>Quay.io</h3>
+         <h3>Quay</h3>
          <p style="font-size: 12px; -webkit-text-adjust: none">
            CoreOS, Inc<br>
            https://coreos.com<br>

util/useremails.py

@@ -147,7 +147,7 @@ def send_org_invite_email(member_name, member_email, orgname, team, adder, code)
 def send_invoice_email(email, contents):
   # Note: This completely generates the contents of the email, so we don't use the
   # normal template here.
-  msg = Message('Quay.io payment received - Thank you!', recipients=[email])
+  msg = Message('Quay payment received - Thank you!', recipients=[email])
   msg.html = contents
   mail.send(msg)