Merge branch '4.4'

* 4.4:
  [Debug] remove return types that break FC badly
  [Mailer][MailchimpBridge] Don't send address names if empty string
  [ExpressionLanguage][Lexer] Exponential format for number
  [Mailer] Fix SES Message Id retrieval
  Add .gitignore to .gitattributes

.gitattributes

@@ -1,2 +1,3 @@
 /Tests export-ignore
 /phpunit.xml.dist export-ignore
+/.gitignore export-ignore