Merge pull request #55 in ZP/z-push from bugfix/ZP-702-Attachments-are-1-or-2-bytes-short to develop

* commit 'bb60677f':
  ZP-702 Implement seeking capability to MAPIStreamWrapper. Add stream size to log output.
  ZP-702 Attachments are 1 or 2 bytes short. Released under the Affero GNU General Public License (AGPL) version 3. Fixed empty attachment data written, because stream was not at the beginning eg. by a previous call to fstat. Also logging now number of bytes written and not length of stream, to be able to detect similar problems.
  ZP-702 Implement plain and base64 encoded stream support into the wbxml encoder and streamer. Removed padding filter and added a null-char-replace filter used when streaming plain streams (tested but not part of this ticket).
  ZP-702 Attachments are 1 or 2 bytes short if size is not 3 byte aligned. Released under the Affero GNU General Public License (AGPL) version 3.