changes fiew - show only differences / hide trivial (comments and whitespaces...)

A pimped changes fiew would be nice, so I don't need to start it via beyond compare to see the facts. Most importent is the reducing to changes (diff view in bc - whith adjustable pre and post code parts) and to hide changed comments / whitespaces (triv. button in bc - with selectable: whitespace/ comments / case changes,....)