Remove duplicate entries in the method index, fix attribute links

I'm not sure why exactly there are duplicate entires, but this
seems to fix it.

The links for the attributes were incorrect, since hanna uses
attribute-* as the anchor for attributes.  Looks like both
respond to aref, so just use that.
Merge pull request #10 from jeremyevans/master

Remove duplicate entries in the method index, fix attribute links