Delete Alert: display file name and file count within alert

Fixes #1691 (closed)

Two problems with this:

1. Need to translate 4 new strings into all languages besides English
2. The code is quite ugly. I receive a VLCMLObject array, and need to cast each object into an Artist/Album/etc to get the total count of items. I then need to cast the first object to write the filename. If there is another way to get a filename from a VLCMLObject, I would love to know.