Consider directories for "exclusive_apps" setting

[LoB]

Hey devs,

I have a lot of computer games on my PC. When playing, I like the exclusive_app configuration which saves me from deactivating and reactivating BOINC manually. Thus, it's very timeconsuming to add all my exclusive applications. Since most of them are located in/below the same directory, a directory-wise exclusive mode would help alot.

So, instead of

    <exclusive_app>foo.exe</exclusive_app>

I would like to be able to add:

    <exclusive_app_dir>C:\bar\</exclusive_app_dir>