Add optional parameter for changed/added/del/unknown files to commands.dodiff This makes it possible to avoid a call into repo.changes if the details of what has changed is already known

+ hg init
+ hg add a
+ hg commit -m commit #0 -d 0 0
a
+ hg add b
+ hg commit -m commit #1 -d 0 0
+ hg co 0
a