Support optional Source, parse from header

The Email ``from`` header is either formatted as ``name <address>`` or ``address``.

This commit will use `parseaddr` to extract a ``(name, address)`` tuple, which we will use the ``address`` to check if it's verified.

Also support the case where ``Source`` is omitted (which AWS requires the ``from`` header to be set).

moto/ses/responses.py

@@ -75,7 +75,10 @@ class EmailResponse(BaseResponse):
         return template.render(message=message)
 
     def send_raw_email(self):
-        source = self.querystring.get('Source')[0]
+        source = self.querystring.get('Source')
+        if source is not None:
+            source, = source
+
         raw_data = self.querystring.get('RawMessage.Data')[0]
         raw_data = base64.b64decode(raw_data)
         if six.PY3: