Adding automatic tab name etc.

by changing the tab name to the console name (if it's not null) or "Current folder: command"

because it's useful

Changing the command separator from - to : because a file or folder name can contain - (so that it's less clear if the delimiter is part of a file or folder name or not)

Removing m_strTitle, SetTitle, OnEditRenameTab  because

* it reduce complexity
* they have limited use