Pretend mode for 'titlecase' plugin

I am normalizing my database, and the new title-case plugin would be a great help. It's great on imports, where you can still accept the modified titles. To apply it to a existing query, it would be nice if it would support a pretend mode (`-p`), to show what it will do before modifying data.

Additionally a `-a` mode to apply to album data would also be great.