[BW]: [NIP] Implemented Draft folder storage. Still has problems:
- new email entry is created in the Drafts folder even already stored mail is again edited - this is caused by backend problems
- loading file attachment from saved mail is not yet implemented.
Merge branch 'master' of https://github.com/InvictusInnovations/keyhotee

Resolved Conflicts:
	KeyhoteeMainWindow.cpp
[BW]: [NIP] Subject/Recipient/attachment list changes should switch document into modified state.