new options to deal with pathname matching

[courtney-rosenthal]

I've got some backup volumes where I'm trying to find duplicate files. For this I need to look at filenames, as well as contents and permissions. Here are some new options that do that.

-b compares file basenames, and considers matches only if they are the same

-P strips a number of directory components (similar to path -p), and considers matches only if the names are the same.

[reikred]

This feature is exactly what I need, really wish this feature could be merged.