[BW]: [NIP] Preliminary changes related to blocking automatically loading of images into mail editor/viewer.
[BW]: [Ign] Code cleanup.
Merge branch 'master' into local_work

Conflicts:
	Mail/MailViewer.ui
	Mail/Mailbox.cpp
	Mail/TMessageEdit.cpp
	Mail/TMessageEdit.hpp
	Mail/maileditorwindow.cpp
[BW]: [NIP] Further development related to control over external image autoloading.