Filters would not accept apostrophes, now they do. Thanks Sean Cashin (http://github.com/scashin133)!
I am not sure about this, since I haven't been able to find documentation about what this does. This should work, though. Cleanup of comments and exceptions, adds specification for Filter.ex and a parser method.
Pretty much rewrote the code. It now also responds to respond_to? correctly. Most of that symbol manipulation is now in just one place.