Feature Request: Mass "Copy to Output Directory" selection

At present, files can be copied to the output directory at compilation time by:

1. Selecting the file in the Projects tab
2. Changing "Never" to "Always" or "Preserve Newest" for the "Copy to Output Directory" in the properties tab

However, only one file can be so designated in that manner at a time.  If many files need to be copied in this manner, it would be preferable to do it all at once, with multiple file selection.  Perhaps we could support this in a future version?

Alternatively, enabling the option at the folder level ("copy this folder to the output directory") would serve a similar purpose.

Just a suggestion!

Thanks for your excellent work maintaining this useful project.