Added Delete confirmation prior to deletion

This allows the user to confirm his/her deletions instead of just dumping them without a second thought.  Since deletions are very final (file-based content with no version control), I feel a confirmation is pretty necessary.

### Caveat

This does add bootstrap's javascript and jquery.  I did take notice that the entire tool is JS-free, and if this was intentional and you'd like to keep it that way let me know, because I have another way of doing this.