Changes:
- added: a constant for max embedded attachment size (general)
- fixed: typo in ASProtocolCommands (general)
- added: basic remote wipe functionality (ics)
- added: inline images in mails for some devices (ics)
- added: search in global address book (ics)
- added: contact picture support (ics)
- fixed: android style remote wipe (ics)
- fixed: check if function mapi_inetmapi_imtoinet exists (ics)
- fixed: set a device's wipe time (ics)
- fixed: added missing function headers (diffbackend)