Roderick Usher's library, etc. 

I have moved the section on Allusions and References to other works of Art (or whatever it was called) into a subsection of Analysis along with Usher's library. I have simplified it a bit and removed some unsourced speculation that a line of Poe's was inspired by a painting of Fuseli. I'm not convinced it's 100% the way to go, but I'm worried about how much undue weight this section is being given compared to more important encyclopedic aspects of the story. Feel free to disagree. I think more clean up is needed, and I will probably soon merge the article on The Mad Trist into this section as well.