#149 New action: unfold only subdirectories where operation is required

[Yves Martin]

Hello,
I am using 0.9.96 on Debian Wheezy and I would find useful to get a new action in "Directory" menu to unfold only subdirectories where an operation is required.
That way, a single action allow to see files to operate in a shorter listing.

Sorry if my request is already implemented in 0.9.98, I was lazy to get and compile sources to compare.

Many thanks for your work on kdiff3
Regards
Yves