Merge pull request #197 in ZP/z-push from feature/ZP-821-integrate-autoloading-for-backends to develop

* commit 'e516b7ed':
  ZP-821 Updated composer.json to include backend folder, removed includes from Combined, IMAP, MailDir, VCardDir and Zarafa backends, removed includes from Zarafa's subcomponents, removed include in InterProcessData, added config include to IpcMemcachedProvider, fixed typo in StringStreamWrapper, fixed typos of MAPIStreamWrapper.