diff mode highlight

[Neal Becker]

I was pleasantly surprised to find that in diff mode I can select a hunk and 
apply it (in reverse).  Nice following C-x v = to show what's changed, and 
decide to reverse a change.

Even nicer would be to highlight the selected hunk (maybe color?) to show what 
would be applied.

Nicer still might be to allow selection of multiple hunks, highlighting them as 
they are selected.